2020-10-20T20:31:35Z
https://hrcak.srce.hr/oai/
oai:hrcak.srce.hr:635
2008-06-03
journal:39
Variational inequality and complementarity problem in locally convex Hausdorff topological vector space
Nanda, S.
variational inequality; Hausdorff topological vector space
The purpose of this paper is to study variational inequality and
complementarity problem in a locally convex Hausdorff topological
vector space.
Department of Mathematics, University of Osijek
2005
text
info:eu-repo/semantics/article
info:eu-repo/semantics/publishedVersion
application/pdf
https://hrcak.srce.hr/635
https://hrcak.srce.hr/file/1301
Mathematical Communications
ISSN 1331-0623 (Print)
ISSN 1848-8013 (Online)
Volume 10
Issue 2
eng
info:eu-repo/semantics/openAccess
The full text of articles published in this journal can be used free of charge for personal and educational purposes while respecting authors' and publisher's copyrights. Annual subscription to printed copies is USD 50.00. Members of the Osijek Mathematical Society and the Mathematical Club of the Department of Mathematics receive this journal free of charge.
oai:hrcak.srce.hr:636
2008-06-03
journal:39
A common unique fixed point result in metric spaces involving generalised altering distances
Choudhury, B. S.
generalised altering distances; metric space; fixed point
In this paper we work out a unique common fixed point result for two self-mappings defined on a complete metric space. These mappings are assumed to satisfy a contractive inequality which involves two generalised altering distances.
Department of Mathematics, University of Osijek
2005
text
info:eu-repo/semantics/article
info:eu-repo/semantics/publishedVersion
application/pdf
https://hrcak.srce.hr/636
https://hrcak.srce.hr/file/1303
Mathematical Communications
ISSN 1331-0623 (Print)
ISSN 1848-8013 (Online)
Volume 10
Issue 2
eng
info:eu-repo/semantics/openAccess
The full text of articles published in this journal can be used free of charge for personal and educational purposes while respecting authors' and publisher's copyrights. Annual subscription to printed copies is USD 50.00. Members of the Osijek Mathematical Society and the Mathematical Club of the Department of Mathematics receive this journal free of charge.
oai:hrcak.srce.hr:637
2008-06-03
journal:39
Fixed points of asymptotically regular mappings
Ćirić, Lj.
fixed point; asymptotically regular mapping
Two general fixed point theorems for asymptotically regular self-mappings on a metric space X which satisfy the contractive condition (1) below are proved. Our results extend and generalize results of Sharma and Yuel [4] and Guay and Singh [3].
Department of Mathematics, University of Osijek
2005
text
info:eu-repo/semantics/article
info:eu-repo/semantics/publishedVersion
application/pdf
https://hrcak.srce.hr/637
https://hrcak.srce.hr/file/1304
Mathematical Communications
ISSN 1331-0623 (Print)
ISSN 1848-8013 (Online)
Volume 10
Issue 2
eng
info:eu-repo/semantics/openAccess
The full text of articles published in this journal can be used free of charge for personal and educational purposes while respecting authors' and publisher's copyrights. Annual subscription to printed copies is USD 50.00. Members of the Osijek Mathematical Society and the Mathematical Club of the Department of Mathematics receive this journal free of charge.
oai:hrcak.srce.hr:638
2008-06-03
journal:39
A fixed fuzzy point for fuzzy mapping in complete metric spaces
Turkoglu, D.
Rhoades, B. E.
fixed point; fuzzy mapping; intuitionistic fuzzy set
In this paper, we prove a fixed fuzzy point theorem for
fuzzy mappings over a complete metric space.
Department of Mathematics, University of Osijek
2005
text
info:eu-repo/semantics/article
info:eu-repo/semantics/publishedVersion
application/pdf
https://hrcak.srce.hr/638
https://hrcak.srce.hr/file/1305
Mathematical Communications
ISSN 1331-0623 (Print)
ISSN 1848-8013 (Online)
Volume 10
Issue 2
eng
info:eu-repo/semantics/openAccess
The full text of articles published in this journal can be used free of charge for personal and educational purposes while respecting authors' and publisher's copyrights. Annual subscription to printed copies is USD 50.00. Members of the Osijek Mathematical Society and the Mathematical Club of the Department of Mathematics receive this journal free of charge.
oai:hrcak.srce.hr:639
2008-06-03
journal:39
GS-deltoids in GS-quasigroups
Kolar-Begović, Z.
Volenec, V.
GS-quasigroup; GS-deltoid
A "geometric'' concept of the GS-deltoid is introduced and investigated in the general GS-quasigroup and geometrical interpretation in the GS-quasigroup $C( frac{1}{2}(1+sqrt 5 ))$ is given. The connection of GS-deltoids with parallelograms, GS-trapezoids, DGS-trapezoids and affine regular pentagons in the general GS-quasigroup is obtained.
Department of Mathematics, University of Osijek
2005
text
info:eu-repo/semantics/article
info:eu-repo/semantics/publishedVersion
application/pdf
https://hrcak.srce.hr/639
https://hrcak.srce.hr/file/1307
Mathematical Communications
ISSN 1331-0623 (Print)
ISSN 1848-8013 (Online)
Volume 10
Issue 2
eng
info:eu-repo/semantics/openAccess
The full text of articles published in this journal can be used free of charge for personal and educational purposes while respecting authors' and publisher's copyrights. Annual subscription to printed copies is USD 50.00. Members of the Osijek Mathematical Society and the Mathematical Club of the Department of Mathematics receive this journal free of charge.
oai:hrcak.srce.hr:640
2008-06-03
journal:39
An interesting example concerning convergence of double sequences
Miller, H. I.
Miller-Van, Wieren L.
statistical convergence; double sequences
In a paper recently submitted for publication, it was shown in Theorem 5,that if $s= ( s_{ij})$ is a divergent double sequence and $A= (A^{pq})$is a double sequence of matrix summability methods footnote{satisfying certain specified conditions}, then the set of "subsequences'' of $s$ that are statistically $A$ convergent is of the first Baire category in the set of all "subsequences'' of $s$.
The main result in this paper shows that the above mentioned result is no longer true if $A$ does not satisfy the last of the four conditions on $A$ in Theorem $5$ of cite{7}. Other related matters are considered.
Department of Mathematics, University of Osijek
2005
text
info:eu-repo/semantics/article
info:eu-repo/semantics/publishedVersion
application/x-tex
https://hrcak.srce.hr/640
https://hrcak.srce.hr/file/1308
Mathematical Communications
ISSN 1331-0623 (Print)
ISSN 1848-8013 (Online)
Volume 10
Issue 2
eng
info:eu-repo/semantics/openAccess
The full text of articles published in this journal can be used free of charge for personal and educational purposes while respecting authors' and publisher's copyrights. Annual subscription to printed copies is USD 50.00. Members of the Osijek Mathematical Society and the Mathematical Club of the Department of Mathematics receive this journal free of charge.
oai:hrcak.srce.hr:643
2008-06-03
journal:39
On the periodic solutions of certain fourth and fifth order vector differential equations
Tunç, E.
Nonlinear vector differential equation of fourth and fifth order; periodic solutions
The aim of the present paper is to establish some sufficient
conditions which ensure that equations (1.1) and (1.2) have no
periodic solution other than the trivial solution X=0.
Department of Mathematics, University of Osijek
2005
text
info:eu-repo/semantics/article
info:eu-repo/semantics/publishedVersion
application/pdf
https://hrcak.srce.hr/643
https://hrcak.srce.hr/file/1311
Mathematical Communications
ISSN 1331-0623 (Print)
ISSN 1848-8013 (Online)
Volume 10
Issue 2
eng
info:eu-repo/semantics/openAccess
The full text of articles published in this journal can be used free of charge for personal and educational purposes while respecting authors' and publisher's copyrights. Annual subscription to printed copies is USD 50.00. Members of the Osijek Mathematical Society and the Mathematical Club of the Department of Mathematics receive this journal free of charge.
oai:hrcak.srce.hr:644
2008-06-03
journal:39
On the trivial units in finite commutative group rings
Danchev, P. V.
trivial units; group rings; abelian groups; fields; irreducible polynomials; decompositions; powers
Let G be a finite abelian group and F a finite field. A criterion is found for all units in the group ringFG to be trivial. This attainment is also extended to the general case for arbitrary abelian groups and fields.
Department of Mathematics, University of Osijek
2005
text
info:eu-repo/semantics/article
info:eu-repo/semantics/publishedVersion
application/pdf
https://hrcak.srce.hr/644
https://hrcak.srce.hr/file/1312
Mathematical Communications
ISSN 1331-0623 (Print)
ISSN 1848-8013 (Online)
Volume 10
Issue 2
eng
info:eu-repo/semantics/openAccess
The full text of articles published in this journal can be used free of charge for personal and educational purposes while respecting authors' and publisher's copyrights. Annual subscription to printed copies is USD 50.00. Members of the Osijek Mathematical Society and the Mathematical Club of the Department of Mathematics receive this journal free of charge.
oai:hrcak.srce.hr:645
2008-06-03
journal:39
Metrical relationships in a standard triangle in an isotropic plane
Kolar-Šuper, R.
Kolar-Begović, Z.
Volenec, V.
Beban-Brkić, J.
isotropic plane; triangle; standard triangle
Each allowable triangle of an isotropic plane can be set in a
standard position, in which it is possible to prove geometric properties analytically in a simplified and easier way by means of
the algebraic theory developed in this paper.
Department of Mathematics, University of Osijek
2005
text
info:eu-repo/semantics/article
info:eu-repo/semantics/publishedVersion
application/pdf
https://hrcak.srce.hr/645
https://hrcak.srce.hr/file/1313
Mathematical Communications
ISSN 1331-0623 (Print)
ISSN 1848-8013 (Online)
Volume 10
Issue 2
eng
info:eu-repo/semantics/openAccess
The full text of articles published in this journal can be used free of charge for personal and educational purposes while respecting authors' and publisher's copyrights. Annual subscription to printed copies is USD 50.00. Members of the Osijek Mathematical Society and the Mathematical Club of the Department of Mathematics receive this journal free of charge.
oai:hrcak.srce.hr:646
2008-06-03
journal:39
αβγσ - technology in the triangle geometry
Volenec, V.
barycentric coordinates; triangle geometry
The barycentric coordinates of the most important points and circles and the equations of the most important lines, conics and cubics of the geometry of triangle ABC are expressed by means of numbers
α = cotA, β = cotB, γ = cotC, σ = cotC and σ = α+β+γ.
Department of Mathematics, University of Osijek
2005
text
info:eu-repo/semantics/article
info:eu-repo/semantics/publishedVersion
application/pdf
https://hrcak.srce.hr/646
https://hrcak.srce.hr/file/1314
Mathematical Communications
ISSN 1331-0623 (Print)
ISSN 1848-8013 (Online)
Volume 10
Issue 2
eng
info:eu-repo/semantics/openAccess
The full text of articles published in this journal can be used free of charge for personal and educational purposes while respecting authors' and publisher's copyrights. Annual subscription to printed copies is USD 50.00. Members of the Osijek Mathematical Society and the Mathematical Club of the Department of Mathematics receive this journal free of charge.
oai:hrcak.srce.hr:647
2008-06-03
journal:39
Some new Menon designs with parameters (196,91,42)
Crnković, D.
symmetric design; Menon design; Hadamard matrix; automorphism group
There are exactly 54 symmetric (196,91,42) designs admitting an
automorphism group isomorphic to $Frob_{13 cdot 6} times Z_3$ acting with orbit size distribution (1,13,13,13,39,39,39,39) for
blocks and points. For 50 of these designs the full automorphism group
has order 234 and is isomorphic to $Frob_{13 cdot 6} times Z_3$.
The remaining four designs have $Frob_{13 cdot 6} times Frob_{7 cdot 3}$ as a full automorphism group.Among these designs there are 18 self-dual designs and 18 pairs of mutually dual ones.
The derived designs (with respect to the fixed block) of the four designs with a full automorphism group of order 1638 are cyclic.
Department of Mathematics, University of Osijek
2005
text
info:eu-repo/semantics/article
info:eu-repo/semantics/publishedVersion
application/pdf
https://hrcak.srce.hr/647
https://hrcak.srce.hr/file/1315
Mathematical Communications
ISSN 1331-0623 (Print)
ISSN 1848-8013 (Online)
Volume 10
Issue 2
eng
info:eu-repo/semantics/openAccess
The full text of articles published in this journal can be used free of charge for personal and educational purposes while respecting authors' and publisher's copyrights. Annual subscription to printed copies is USD 50.00. Members of the Osijek Mathematical Society and the Mathematical Club of the Department of Mathematics receive this journal free of charge.
oai:hrcak.srce.hr:655
2008-06-03
journal:39
One-dimensional flow of a compressible viscous micropolar fluid: The Cauchy problem
Mujaković, N.
micropolar fluid; the Cauchy problem; strong solution; weak convergence
The Cauchy problem for one-dimensional flow of a compressible viscous heat-conducting micropolar fluid is considered.
It is assumed that the fluid is thermodynamically perfect and polytropic.
A corresponding initial-boundary value problem has a unique strong solution on ]0,1[×]0,T[, for each T>0. By using this result we construct a sequence of approximate solutions which converges to a solution of the Cauchy problem.
Department of Mathematics, University of Osijek
2005
text
info:eu-repo/semantics/article
info:eu-repo/semantics/publishedVersion
application/pdf
https://hrcak.srce.hr/655
https://hrcak.srce.hr/file/1329
Mathematical Communications
ISSN 1331-0623 (Print)
ISSN 1848-8013 (Online)
Volume 10
Issue 1
eng
info:eu-repo/semantics/openAccess
The full text of articles published in this journal can be used free of charge for personal and educational purposes while respecting authors' and publisher's copyrights. Annual subscription to printed copies is USD 50.00. Members of the Osijek Mathematical Society and the Mathematical Club of the Department of Mathematics receive this journal free of charge.
oai:hrcak.srce.hr:656
2008-06-03
journal:39
The fixed point property for arc component preserving mappings of non-metric tree-like continua
Lončar, I.
continuum; fixed point property; inverse system
The main purpose of this paper is to study the fixed point property of
non-metric tree-like continua. Using the inverse systems method, it is proved that if X is a non-metric tree-like continuum and if f:X→X is a mapping which sends each arc component into itself,
then f has the fixed point property.
Department of Mathematics, University of Osijek
2005
text
info:eu-repo/semantics/article
info:eu-repo/semantics/publishedVersion
application/pdf
https://hrcak.srce.hr/656
https://hrcak.srce.hr/file/1330
Mathematical Communications
ISSN 1331-0623 (Print)
ISSN 1848-8013 (Online)
Volume 10
Issue 1
eng
info:eu-repo/semantics/openAccess
The full text of articles published in this journal can be used free of charge for personal and educational purposes while respecting authors' and publisher's copyrights. Annual subscription to printed copies is USD 50.00. Members of the Osijek Mathematical Society and the Mathematical Club of the Department of Mathematics receive this journal free of charge.
oai:hrcak.srce.hr:657
2008-06-03
journal:39
Independent sets and independent dominating sets in the strong product of paths and cycles
Klobučar, A.
path; cycle; strong product; independent dominating set; independent set
In this paper we will consider independent sets and independent dominating sets in the strong product of two paths,two cycles and a path and a cycle.
Department of Mathematics, University of Osijek
2005
text
info:eu-repo/semantics/article
info:eu-repo/semantics/publishedVersion
application/pdf
https://hrcak.srce.hr/657
https://hrcak.srce.hr/file/1331
Mathematical Communications
ISSN 1331-0623 (Print)
ISSN 1848-8013 (Online)
Volume 10
Issue 1
eng
info:eu-repo/semantics/openAccess
The full text of articles published in this journal can be used free of charge for personal and educational purposes while respecting authors' and publisher's copyrights. Annual subscription to printed copies is USD 50.00. Members of the Osijek Mathematical Society and the Mathematical Club of the Department of Mathematics receive this journal free of charge.
oai:hrcak.srce.hr:658
2008-06-03
journal:39
A generalized q-numerical range
Rajić, R.
C*-algebra; Hilbert C*-module; adjointable operator; C-numerical range of an operator; q-numerical range of an operator
For a given $q in kom$ with $|q| le 1$, we study the $C$-numerical range of a Hilbert space operator where $C$ is an operator of the form
[
left( begin{array}{ccc}
qI_n & sqrt{1-|q|^2}I_n \
0_n & 0_n
end{array} right)
oplus 0.
]
Some known results on the $q$-numerical range are extended to this set.
Department of Mathematics, University of Osijek
2005
text
info:eu-repo/semantics/article
info:eu-repo/semantics/publishedVersion
application/pdf
https://hrcak.srce.hr/658
https://hrcak.srce.hr/file/1332
Mathematical Communications
ISSN 1331-0623 (Print)
ISSN 1848-8013 (Online)
Volume 10
Issue 1
eng
info:eu-repo/semantics/openAccess
The full text of articles published in this journal can be used free of charge for personal and educational purposes while respecting authors' and publisher's copyrights. Annual subscription to printed copies is USD 50.00. Members of the Osijek Mathematical Society and the Mathematical Club of the Department of Mathematics receive this journal free of charge.
oai:hrcak.srce.hr:659
2008-06-03
journal:39
On sequences of positive integers containing arithmetical progressions
Šalát, T.
Tomanová, J.
density; Baire category; Lebesgue measure; Hausdorff dimension; arithmetic progression
We study from the metrical and topological point of view the properties of sequences of positive integers which consist in fact that the sequences contain arbitrarily long arithmetical progressions and infinite arithmetical progressions, respectively. At the end of the paper we give another solution of the problem of R. C.
Buck concerning the class $mathcal{D}_{mu}$ of all $A
subseteq N$ having Buck's measure $mu(A)$.
Department of Mathematics, University of Osijek
2005
text
info:eu-repo/semantics/article
info:eu-repo/semantics/publishedVersion
application/pdf
https://hrcak.srce.hr/659
https://hrcak.srce.hr/file/1333
Mathematical Communications
ISSN 1331-0623 (Print)
ISSN 1848-8013 (Online)
Volume 10
Issue 1
eng
info:eu-repo/semantics/openAccess
The full text of articles published in this journal can be used free of charge for personal and educational purposes while respecting authors' and publisher's copyrights. Annual subscription to printed copies is USD 50.00. Members of the Osijek Mathematical Society and the Mathematical Club of the Department of Mathematics receive this journal free of charge.
oai:hrcak.srce.hr:660
2008-06-03
journal:39
Lacunary statistical convergence of double sequences
Patterson, R. F.
Savaş, E.
double lacunary sequences; P-convergent
In 1978 Freedman, Sember, and Raphael presented a definition for
lacunary refinement as follows: $rho={bar{k}_{r}}$ is called a
lacunary refinement of the lacunary sequence $theta ={k_{r}}$
if ${k_{r}}subseteq {bar{k}_{r}}$. They use this definition
to present one side inclusion theorem with respect to the refined
and non refined sequence. In 2000 Li presented the other side of
the inclusion. In this paper we shall present a multidimensional
analogue to the notion of refinement of lacunary sequences and use
this definition to present both sides of the above inclusion
theorem. In addition, we shall also present a notion of double
lacunary statistically Cauchy and use this definition to establish
that it is equivalent to the $S_{theta_{r,s}}$-P-convergence.
Department of Mathematics, University of Osijek
2005
text
info:eu-repo/semantics/article
info:eu-repo/semantics/publishedVersion
application/pdf
https://hrcak.srce.hr/660
https://hrcak.srce.hr/file/1334
Mathematical Communications
ISSN 1331-0623 (Print)
ISSN 1848-8013 (Online)
Volume 10
Issue 1
eng
info:eu-repo/semantics/openAccess
The full text of articles published in this journal can be used free of charge for personal and educational purposes while respecting authors' and publisher's copyrights. Annual subscription to printed copies is USD 50.00. Members of the Osijek Mathematical Society and the Mathematical Club of the Department of Mathematics receive this journal free of charge.
oai:hrcak.srce.hr:661
2008-06-03
journal:39
On the strong laws of large numbers for ρ-mixing sequences
Cai, G.
Wu, H.
ρ-mixing sequences; NA sequences; strong laws of large numbers; moment conditions
The connection between general moment conditions and the applicability of strong laws of large numbers for a sequence of identically distributed ρ-mixing random variables are obtained.
The results obtained generalize the result of Petrov (1996, Statist. Probab. Lett. 26, 377-380) to ρ-mixing sequences and NA sequences.
Department of Mathematics, University of Osijek
2005
text
info:eu-repo/semantics/article
info:eu-repo/semantics/publishedVersion
application/pdf
https://hrcak.srce.hr/661
https://hrcak.srce.hr/file/1335
Mathematical Communications
ISSN 1331-0623 (Print)
ISSN 1848-8013 (Online)
Volume 10
Issue 1
eng
info:eu-repo/semantics/openAccess
The full text of articles published in this journal can be used free of charge for personal and educational purposes while respecting authors' and publisher's copyrights. Annual subscription to printed copies is USD 50.00. Members of the Osijek Mathematical Society and the Mathematical Club of the Department of Mathematics receive this journal free of charge.
oai:hrcak.srce.hr:662
2008-06-03
journal:39
I and I* convergent function sequences
Gezer, F.
Karakuş, S.
pointwise and uniform convergence; I-convergence; I*-convergence
In this paper, we introduce the concepts of I-pointwise
convergence, I-uniform convergence,I*-pointwise convergence and I*-uniform convergence of function sequences and then we examine the relation between them.
Department of Mathematics, University of Osijek
2005
text
info:eu-repo/semantics/article
info:eu-repo/semantics/publishedVersion
application/pdf
https://hrcak.srce.hr/662
https://hrcak.srce.hr/file/1336
Mathematical Communications
ISSN 1331-0623 (Print)
ISSN 1848-8013 (Online)
Volume 10
Issue 1
eng
info:eu-repo/semantics/openAccess
The full text of articles published in this journal can be used free of charge for personal and educational purposes while respecting authors' and publisher's copyrights. Annual subscription to printed copies is USD 50.00. Members of the Osijek Mathematical Society and the Mathematical Club of the Department of Mathematics receive this journal free of charge.
oai:hrcak.srce.hr:663
2008-06-03
journal:39
The equivalence of Picard, Mann and Ishikawa iterations dealing with quasi-contractive operators
Şolutuz, Ş. M.
Picard iteration; Mann iteration; Ishikawa iteration; quasi-contractive operators
We show that the Ishikawa iteration, the corresponding Mann iteration and the
Picard iteration are equivalent when applied to quasi-contractive operators.
Department of Mathematics, University of Osijek
2005
text
info:eu-repo/semantics/article
info:eu-repo/semantics/publishedVersion
application/pdf
https://hrcak.srce.hr/663
https://hrcak.srce.hr/file/1337
Mathematical Communications
ISSN 1331-0623 (Print)
ISSN 1848-8013 (Online)
Volume 10
Issue 1
eng
info:eu-repo/semantics/openAccess
The full text of articles published in this journal can be used free of charge for personal and educational purposes while respecting authors' and publisher's copyrights. Annual subscription to printed copies is USD 50.00. Members of the Osijek Mathematical Society and the Mathematical Club of the Department of Mathematics receive this journal free of charge.
oai:hrcak.srce.hr:664
2008-06-03
journal:39
On the number of hamiltonian groups
Horvat, B.
Jaklič, G.
Pisanski, T.
group; number; sequence; normal subgroup; abelian; hamiltonian
Finite hamiltonian groups are counted. The sequence of numbers of all groups of order n whose all subgroups are normal and the sequence of numbers of all groups of order less than or equal to n whose all subgroups are normal are presented.
Department of Mathematics, University of Osijek
2005
text
info:eu-repo/semantics/article
info:eu-repo/semantics/publishedVersion
application/pdf
https://hrcak.srce.hr/664
https://hrcak.srce.hr/file/1339
Mathematical Communications
ISSN 1331-0623 (Print)
ISSN 1848-8013 (Online)
Volume 10
Issue 1
eng
info:eu-repo/semantics/openAccess
The full text of articles published in this journal can be used free of charge for personal and educational purposes while respecting authors' and publisher's copyrights. Annual subscription to printed copies is USD 50.00. Members of the Osijek Mathematical Society and the Mathematical Club of the Department of Mathematics receive this journal free of charge.
oai:hrcak.srce.hr:665
2008-06-03
journal:39
A class of random complementarity problems in Hilbert spaces
Chang, S. S.
Lee, H. W. J.
Wu, D. P.
random complementarity problem; random variational inequality; random mapping; random fixed point
The purpose of this paper is to study the existence and approximation problem of random solutions for a class of random complementarity problems in the setting of Hilbert spaces.
Department of Mathematics, University of Osijek
2005
text
info:eu-repo/semantics/article
info:eu-repo/semantics/publishedVersion
application/pdf
https://hrcak.srce.hr/665
https://hrcak.srce.hr/file/1340
Mathematical Communications
ISSN 1331-0623 (Print)
ISSN 1848-8013 (Online)
Volume 10
Issue 1
eng
info:eu-repo/semantics/openAccess
The full text of articles published in this journal can be used free of charge for personal and educational purposes while respecting authors' and publisher's copyrights. Annual subscription to printed copies is USD 50.00. Members of the Osijek Mathematical Society and the Mathematical Club of the Department of Mathematics receive this journal free of charge.
oai:hrcak.srce.hr:675
2008-06-03
journal:39
On dendrites with the ΩEP-property
Charatonik, J. J.
connected function; connectivity function; continuum; Darboux function; dendrite; end points; eventually periodic point; mapping;periodic point; recurrent point; tree
A space X has the ΩEP-property if for each self-mapping the set of
nonwandering points is contained in the closure of the set of eventually
periodic points. Dendrites having this property are investigated. Several of their properties dispersed in the literature are recalled and some new results are presented.
Department of Mathematics, University of Osijek
2004
text
info:eu-repo/semantics/article
info:eu-repo/semantics/publishedVersion
application/x-tex
https://hrcak.srce.hr/675
https://hrcak.srce.hr/file/1359
Mathematical Communications
ISSN 1331-0623 (Print)
ISSN 1848-8013 (Online)
Volume 9
Issue 2
eng
info:eu-repo/semantics/openAccess
The full text of articles published in this journal can be used free of charge for personal and educational purposes while respecting authors' and publisher's copyrights. Annual subscription to printed copies is USD 50.00. Members of the Osijek Mathematical Society and the Mathematical Club of the Department of Mathematics receive this journal free of charge.
oai:hrcak.srce.hr:677
2008-06-03
journal:39
Jensen's inequality for nonconvex functions
Zlobec, S.
Jensen's inequality; convexifiable function; arithmetic mean theorem
Jensen's inequality is formulated for convexifiable (generally nonconvex) functions.
Department of Mathematics, University of Osijek
2004
text
info:eu-repo/semantics/article
info:eu-repo/semantics/publishedVersion
application/pdf
https://hrcak.srce.hr/677
https://hrcak.srce.hr/file/1362
Mathematical Communications
ISSN 1331-0623 (Print)
ISSN 1848-8013 (Online)
Volume 9
Issue 2
eng
info:eu-repo/semantics/openAccess
The full text of articles published in this journal can be used free of charge for personal and educational purposes while respecting authors' and publisher's copyrights. Annual subscription to printed copies is USD 50.00. Members of the Osijek Mathematical Society and the Mathematical Club of the Department of Mathematics receive this journal free of charge.
oai:hrcak.srce.hr:678
2008-06-03
journal:39
Existence and approximation of solutions of a system of differential equations of Volterra type
Vrdoljak, B.
Omerspahić, A.
Volterra system; existence and behaviour of solutions; approximation of solutions
The present paper deals with the nonlinear systems of
differential equations of Volterra type regarding the existence,
behaviour, approximation and stability of their definite solutions, all
solutions in a corresponding region or parametric classes of solutions on an unbounded interval. The approximate solutions with precise error estimates are determined. The theory of qualitative analysis of differential equations and the topological retraction method are used.
Department of Mathematics, University of Osijek
2004
text
info:eu-repo/semantics/article
info:eu-repo/semantics/publishedVersion
application/pdf
https://hrcak.srce.hr/678
https://hrcak.srce.hr/file/1363
Mathematical Communications
ISSN 1331-0623 (Print)
ISSN 1848-8013 (Online)
Volume 9
Issue 2
eng
info:eu-repo/semantics/openAccess
The full text of articles published in this journal can be used free of charge for personal and educational purposes while respecting authors' and publisher's copyrights. Annual subscription to printed copies is USD 50.00. Members of the Osijek Mathematical Society and the Mathematical Club of the Department of Mathematics receive this journal free of charge.
oai:hrcak.srce.hr:680
2008-06-03
journal:39
Diophantine quadruples in the ring Z[√2]
Franušić, Z.
Diophantine quadruples; difference of squares; quadratic fields; Pellian equations
The set of integers of the quadratic field Q(√d)has the property D(z) if the product of its any two distinct elements increased by z is a perfct square in Q(√d). In case d=2, we prove that there exist infinitely many integer quadruples with the property D(z) if and only if z can be represented as a difference of two squares of integers in Q(√2).
Department of Mathematics, University of Osijek
2004
text
info:eu-repo/semantics/article
info:eu-repo/semantics/publishedVersion
application/pdf
https://hrcak.srce.hr/680
https://hrcak.srce.hr/file/1366
Mathematical Communications
ISSN 1331-0623 (Print)
ISSN 1848-8013 (Online)
Volume 9
Issue 2
eng
info:eu-repo/semantics/openAccess
The full text of articles published in this journal can be used free of charge for personal and educational purposes while respecting authors' and publisher's copyrights. Annual subscription to printed copies is USD 50.00. Members of the Osijek Mathematical Society and the Mathematical Club of the Department of Mathematics receive this journal free of charge.
oai:hrcak.srce.hr:681
2008-06-03
journal:39
Stability of Mann and Ishikawa iterative processes with errors for a class of nonlinear variational inclusions
Gu, F.
Lu, J.
variational inclusion; variational inequality; accretive mapping; Ishikawa iterative process with errors; stability
Under the lack of the condition , some new convergence and stability theorems of Mann and Ishikawa iterative processes with errors for solutions to variational inclusions involving accretive mappings in real
reflexive Banach spaces are established. The main results of this
paper extend and improve the corresponding results obtained by
Chang, Ding, Hassouni and Moudafi, Huang, Kazmi, Noor, Siddiqi and
Ansari and Zeng.
Department of Mathematics, University of Osijek
2004
text
info:eu-repo/semantics/article
info:eu-repo/semantics/publishedVersion
application/pdf
https://hrcak.srce.hr/681
https://hrcak.srce.hr/file/1367
Mathematical Communications
ISSN 1331-0623 (Print)
ISSN 1848-8013 (Online)
Volume 9
Issue 2
eng
info:eu-repo/semantics/openAccess
The full text of articles published in this journal can be used free of charge for personal and educational purposes while respecting authors' and publisher's copyrights. Annual subscription to printed copies is USD 50.00. Members of the Osijek Mathematical Society and the Mathematical Club of the Department of Mathematics receive this journal free of charge.
oai:hrcak.srce.hr:683
2008-06-03
journal:39
Stammler's circles, Stammler's triangle and Morley's triangle of a given triangle
Kolar-Šuper, R.
Volenec, V.
Stammler's circles; Stammler's triangle; Morley's triangle
By means of complex coordinates shorter proofs of the results of L. Stammler [1], [2] will be given, plus several statements connected with them.
Department of Mathematics, University of Osijek
2004
text
info:eu-repo/semantics/article
info:eu-repo/semantics/publishedVersion
application/pdf
https://hrcak.srce.hr/683
https://hrcak.srce.hr/file/1370
Mathematical Communications
ISSN 1331-0623 (Print)
ISSN 1848-8013 (Online)
Volume 9
Issue 2
eng
info:eu-repo/semantics/openAccess
The full text of articles published in this journal can be used free of charge for personal and educational purposes while respecting authors' and publisher's copyrights. Annual subscription to printed copies is USD 50.00. Members of the Osijek Mathematical Society and the Mathematical Club of the Department of Mathematics receive this journal free of charge.
oai:hrcak.srce.hr:685
2008-06-03
journal:39
Total forcing number of the triangular grid
Vukičević, D.
Sedlar, J.
forcing matchings; total forcing matchings; grid; triangular grid; extremal problem
Let $T$ be a square triangular grid with $n$ rows and columns of vertices and $n$ an even number. A set of edges $Esubset E(T)$ completely determines perfect matchings on $T$ if there are no two different matchings on $T$ coinciding on $E.$ We establish the upper and the lower bound for the smallest value of $left| Eright| ,$ i.e. we show that
begin{equation*}
frac{5}{4}n^{2}-frac{21}{2}n+frac{41}{4}leq left| Eright| leq frac{5}{4}n^{2}+n-2
end{equation*}%
and show that $left| Eright| /left| E(T)right| $ tends
to $5/12$ when $n$ tends to infinity.
Department of Mathematics, University of Osijek
2004
text
info:eu-repo/semantics/article
info:eu-repo/semantics/publishedVersion
application/pdf
https://hrcak.srce.hr/685
https://hrcak.srce.hr/file/1373
Mathematical Communications
ISSN 1331-0623 (Print)
ISSN 1848-8013 (Online)
Volume 9
Issue 2
eng
info:eu-repo/semantics/openAccess
The full text of articles published in this journal can be used free of charge for personal and educational purposes while respecting authors' and publisher's copyrights. Annual subscription to printed copies is USD 50.00. Members of the Osijek Mathematical Society and the Mathematical Club of the Department of Mathematics receive this journal free of charge.
oai:hrcak.srce.hr:686
2008-06-03
journal:39
On path graphs of incidence graphs
Crnković, D.
path graph; bipartite graph; perfect graph; incidence graph
For a given graph $G$ and a positive integer $k$ the $P_k$-path graph $P_k(G)$ has for vertices the set of paths of length $k$ in $G$.
Two vertices are connected in $P_k(G)$ when the intersection of the
corresponding paths forms a path of length $k-1$ in $G$, and their union forms either a cycle or a path of length $k+1$. Path graphs were proposed as a generalization of line graphs.
In this article we investigate some properties of path graphs of bipartite graphs, especially path graphs of incidence graphs of configurations.
Department of Mathematics, University of Osijek
2004
text
info:eu-repo/semantics/article
info:eu-repo/semantics/publishedVersion
application/pdf
https://hrcak.srce.hr/686
https://hrcak.srce.hr/file/1374
Mathematical Communications
ISSN 1331-0623 (Print)
ISSN 1848-8013 (Online)
Volume 9
Issue 2
eng
info:eu-repo/semantics/openAccess
The full text of articles published in this journal can be used free of charge for personal and educational purposes while respecting authors' and publisher's copyrights. Annual subscription to printed copies is USD 50.00. Members of the Osijek Mathematical Society and the Mathematical Club of the Department of Mathematics receive this journal free of charge.
oai:hrcak.srce.hr:687
2008-06-03
journal:39
On some properties of the Lyapunov equation for damped systems
Truhar, N.
Veselić, K.
Damped-vibration; Lyapunov equation; optimization of dampers' viscosities
We consider a damped linear vibrational system whose dampers
depend linearly on the viscosity parameter v. We show that the
trace of the corresponding Lyapunov solution can be represented as
a rational function of v whose poles are the eigenvalues of a
certain skew symmetric matrix. This makes it possible to derive an
asymptotic expansion of the solution in the neighborhood of zero
(small damping).
Department of Mathematics, University of Osijek
2004
text
info:eu-repo/semantics/article
info:eu-repo/semantics/publishedVersion
application/pdf
https://hrcak.srce.hr/687
https://hrcak.srce.hr/file/1375
Mathematical Communications
ISSN 1331-0623 (Print)
ISSN 1848-8013 (Online)
Volume 9
Issue 2
eng
info:eu-repo/semantics/openAccess
The full text of articles published in this journal can be used free of charge for personal and educational purposes while respecting authors' and publisher's copyrights. Annual subscription to printed copies is USD 50.00. Members of the Osijek Mathematical Society and the Mathematical Club of the Department of Mathematics receive this journal free of charge.
oai:hrcak.srce.hr:709
2016-03-18
journal:39
Some diophantine quadruples in the ring Z[√-2]
Abu Muriefah, Fadwa S.
Al-Rashed, A.
quadratic field; diophantine equation
A complex diophantine quadruple with the property D,$(z)$, where $z in $ Z$[sqrt {-2}]$, is a subset of Z$[sqrt {-2}]$ of four elements such that the product of its any two distinct elements increased by $z$ is a perfect square in Z$[sqrt{-2}]$. In the present paper we prove that if $b$ is an odd integer, then there does not exist a diophantine quadruple with the property D$(a + bsqrt{-2})$. For $z=a+bsqrt{-2}$, where $b$ is even, we prove that there exist at least two distinct complex diophantine quadruples if $a$ and $b$ satisfy some congruence conditions.
Department of Mathematics, University of Osijek
2004
text
info:eu-repo/semantics/article
info:eu-repo/semantics/publishedVersion
application/pdf
https://hrcak.srce.hr/709
https://hrcak.srce.hr/file/1421
Mathematical Communications
ISSN 1331-0623 (Print)
ISSN 1848-8013 (Online)
Volume 9
Issue 1
eng
info:eu-repo/semantics/openAccess
The full text of articles published in this journal can be used free of charge for personal and educational purposes while respecting authors' and publisher's copyrights. Annual subscription to printed copies is USD 50.00. Members of the Osijek Mathematical Society and the Mathematical Club of the Department of Mathematics receive this journal free of charge.
oai:hrcak.srce.hr:710
2008-06-03
journal:39
Sub-exponential mixing rate for a class of Markov chains
Klokov, S. A.
Veretennikov, A. Yu.
Markov processes; recurrence; invariant measure; mixing coefficients; sub-exponential convergence
We establish sub-exponential bounds for the β-mixing rate
and for the rate of convergence to invariant measures for discrete
time Markov processes under recurrence type conditions weaker
than used for exponential inequalities and stronger than for
polynomial ones.
Department of Mathematics, University of Osijek
2004
text
info:eu-repo/semantics/article
info:eu-repo/semantics/publishedVersion
application/pdf
https://hrcak.srce.hr/710
https://hrcak.srce.hr/file/1422
Mathematical Communications
ISSN 1331-0623 (Print)
ISSN 1848-8013 (Online)
Volume 9
Issue 1
eng
info:eu-repo/semantics/openAccess
The full text of articles published in this journal can be used free of charge for personal and educational purposes while respecting authors' and publisher's copyrights. Annual subscription to printed copies is USD 50.00. Members of the Osijek Mathematical Society and the Mathematical Club of the Department of Mathematics receive this journal free of charge.
oai:hrcak.srce.hr:712
2008-06-03
journal:39
Fitting affine and orthogonal transformations between two sets of points
Späth, H.
fitting linear transformations; least squares
Let two point sets P and Q be given in $R^n$. We determine a
translation and an affine transformation or an isometry such that the image of Q approximates P as best as possible in the least squares sense.
Department of Mathematics, University of Osijek
2004
text
info:eu-repo/semantics/article
info:eu-repo/semantics/publishedVersion
application/pdf
https://hrcak.srce.hr/712
https://hrcak.srce.hr/file/1425
Mathematical Communications
ISSN 1331-0623 (Print)
ISSN 1848-8013 (Online)
Volume 9
Issue 1
eng
info:eu-repo/semantics/openAccess
The full text of articles published in this journal can be used free of charge for personal and educational purposes while respecting authors' and publisher's copyrights. Annual subscription to printed copies is USD 50.00. Members of the Osijek Mathematical Society and the Mathematical Club of the Department of Mathematics receive this journal free of charge.
oai:hrcak.srce.hr:713
2008-06-03
journal:39
Total domination numbers of cartesian products
Klobučar, A.
path; total dominating set; cartesian product
Let G□H denote the cartesian product of graphs G and H.
Here we determine the total domination numbers of P_5 □P_n and
P_6 □ P_n.
Department of Mathematics, University of Osijek
2004
text
info:eu-repo/semantics/article
info:eu-repo/semantics/publishedVersion
application/pdf
https://hrcak.srce.hr/713
https://hrcak.srce.hr/file/1426
Mathematical Communications
ISSN 1331-0623 (Print)
ISSN 1848-8013 (Online)
Volume 9
Issue 1
eng
info:eu-repo/semantics/openAccess
The full text of articles published in this journal can be used free of charge for personal and educational purposes while respecting authors' and publisher's copyrights. Annual subscription to printed copies is USD 50.00. Members of the Osijek Mathematical Society and the Mathematical Club of the Department of Mathematics receive this journal free of charge.
oai:hrcak.srce.hr:714
2008-06-03
journal:39
Classification of symmetric block design for (71,21,6) with nonabelian group of order 21
Ademaj, E.
Essert, M.
block design; automorphism group; collineation
The existence of symmetric block designs for (71,21,6) was
doubtful until the discovery of Z. Janko and T. van Trung of the
so-called "non-human" design [3]. In this paper we have classified
designs with the above parameters, admitting all possible actions
of the nonabelian group of order 21 on them, which is indeed the
full automorphism group of the Janko-van Trung design. We have
proved that there is only one symmetric block design for (71,21,6), together with its dual, with the Frobenius group of order 21, namely the Janko-van Trung design.
Department of Mathematics, University of Osijek
2004
text
info:eu-repo/semantics/article
info:eu-repo/semantics/publishedVersion
application/pdf
https://hrcak.srce.hr/714
https://hrcak.srce.hr/file/1427
Mathematical Communications
ISSN 1331-0623 (Print)
ISSN 1848-8013 (Online)
Volume 9
Issue 1
eng
info:eu-repo/semantics/openAccess
The full text of articles published in this journal can be used free of charge for personal and educational purposes while respecting authors' and publisher's copyrights. Annual subscription to printed copies is USD 50.00. Members of the Osijek Mathematical Society and the Mathematical Club of the Department of Mathematics receive this journal free of charge.
oai:hrcak.srce.hr:715
2008-06-03
journal:39
Preservation of efficiency and inefficiency classification in data envelopment analysis
Neralić, L.
data envelopment analysis; efficiency; additive model; preservation of efficiency and inefficiency classification; sensitivity analysis; linear programming
Sufficient conditions for simultaneous efficiency preservation of all efficient Decision Making Units (DMUs) and for inefficiency preservation of all inefficient DMUs in the Additive model of Data Envelopment Analysis (DEA) under the simultaneous non-negative perturbations of all data of all DMUs are obtained. An illustrative example is provided.
Department of Mathematics, University of Osijek
2004
text
info:eu-repo/semantics/article
info:eu-repo/semantics/publishedVersion
application/pdf
https://hrcak.srce.hr/715
https://hrcak.srce.hr/file/1428
Mathematical Communications
ISSN 1331-0623 (Print)
ISSN 1848-8013 (Online)
Volume 9
Issue 1
eng
info:eu-repo/semantics/openAccess
The full text of articles published in this journal can be used free of charge for personal and educational purposes while respecting authors' and publisher's copyrights. Annual subscription to printed copies is USD 50.00. Members of the Osijek Mathematical Society and the Mathematical Club of the Department of Mathematics receive this journal free of charge.
oai:hrcak.srce.hr:717
2008-06-03
journal:39
A note on the root subspaces of real semisimple Lie algebras
Kraljević, H.
real semisimple Lie algebra; root systems; reduced roots; root subspaces
In this note we prove that for any two restricted roots $alpha,$ $beta$ of a real semisimple Lie algebra $gg,$ such that $alpha+betanot=0,$ the corresponding root subspaces satisfy $[gg_{alpha},gg_{beta}]=gg_{alpha+beta}$.
Department of Mathematics, University of Osijek
2004
text
info:eu-repo/semantics/article
info:eu-repo/semantics/publishedVersion
application/pdf
https://hrcak.srce.hr/717
https://hrcak.srce.hr/file/1431
Mathematical Communications
ISSN 1331-0623 (Print)
ISSN 1848-8013 (Online)
Volume 9
Issue 1
eng
info:eu-repo/semantics/openAccess
The full text of articles published in this journal can be used free of charge for personal and educational purposes while respecting authors' and publisher's copyrights. Annual subscription to printed copies is USD 50.00. Members of the Osijek Mathematical Society and the Mathematical Club of the Department of Mathematics receive this journal free of charge.
oai:hrcak.srce.hr:718
2008-06-03
journal:39
Quartics in $E^3$ which have a triple point and touch the plane at infinity through the absolute conic
Gorjanc, S.
quartic; triple point
This paper gives the classification of the 4th order surfaces in $E^3$
which have a triple point and touch the plane at infinity at the absolute conic. The classification is made according to the type of the tangent cubic cone at a triple point. Three types with sixteen subtypes are obtained. For these surfaces the homogeneous and parametric equations are derived and each type is illustrated with Mathematica graphics.
Department of Mathematics, University of Osijek
2004
text
info:eu-repo/semantics/article
info:eu-repo/semantics/publishedVersion
application/pdf
https://hrcak.srce.hr/718
https://hrcak.srce.hr/file/1432
Mathematical Communications
ISSN 1331-0623 (Print)
ISSN 1848-8013 (Online)
Volume 9
Issue 1
eng
info:eu-repo/semantics/openAccess
The full text of articles published in this journal can be used free of charge for personal and educational purposes while respecting authors' and publisher's copyrights. Annual subscription to printed copies is USD 50.00. Members of the Osijek Mathematical Society and the Mathematical Club of the Department of Mathematics receive this journal free of charge.
oai:hrcak.srce.hr:719
2008-06-03
journal:39
Circles in barycentric coordinates
Volenec, V.
barycentric coordinates; circle
Let ABC be a fundamental triangle with the area ∆. For a circle K the powers of vertices A,B,C with regard to K divided by 2∆ are said to be the barycentric coordinates of K with respect to triangle ABC. This paper gives some theory and applications of these coordinates.
Department of Mathematics, University of Osijek
2004
text
info:eu-repo/semantics/article
info:eu-repo/semantics/publishedVersion
application/pdf
https://hrcak.srce.hr/719
https://hrcak.srce.hr/file/1433
Mathematical Communications
ISSN 1331-0623 (Print)
ISSN 1848-8013 (Online)
Volume 9
Issue 1
eng
info:eu-repo/semantics/openAccess
The full text of articles published in this journal can be used free of charge for personal and educational purposes while respecting authors' and publisher's copyrights. Annual subscription to printed copies is USD 50.00. Members of the Osijek Mathematical Society and the Mathematical Club of the Department of Mathematics receive this journal free of charge.
oai:hrcak.srce.hr:720
2008-06-03
journal:39
Blanuša double
Orbanić, A.
Pisanski, T.
Randić, M.
Servatius, B.
Blanuša snark; Blanuša double snark; dot product; embeddings
A snark is a non-trivial cubic graph admitting no Tait coloring.
We examine the structure of the two known snarks on 18 vertices, the Blanuša graph and the Blanuša double. By showing that one is of genus 1, the other of genus 2, we obtain maps on the torus and double torus which are not 4-colorable.
The Blanuša graphs appear also to be a counter example for the
conjecture that the orientable genus of a dot product of n Petersen graphs is n-1 (Tinsley and Watkins, 1985).
We also prove that the 6 known snarks of order 20 are all of genus 2.
Department of Mathematics, University of Osijek
2004
text
info:eu-repo/semantics/article
info:eu-repo/semantics/publishedVersion
application/pdf
https://hrcak.srce.hr/720
https://hrcak.srce.hr/file/1435
Mathematical Communications
ISSN 1331-0623 (Print)
ISSN 1848-8013 (Online)
Volume 9
Issue 1
eng
info:eu-repo/semantics/openAccess
The full text of articles published in this journal can be used free of charge for personal and educational purposes while respecting authors' and publisher's copyrights. Annual subscription to printed copies is USD 50.00. Members of the Osijek Mathematical Society and the Mathematical Club of the Department of Mathematics receive this journal free of charge.
oai:hrcak.srce.hr:722
2008-06-03
journal:39
Generalized Veltman models with a root
Vuković, M.
interpretability logic; generalized Veltman semantics
Provability logic is a nonstandard modal logic. Interpretability logic is an extension of provability logic. Generalized Veltman models are Kripke like semantics for interpretability logic. We consider generalized
Veltman models with a root, i.e. r-validity, r-satisfiability and
a consequence relation. We modify Fine's and Rautenberg's proof
and prove non-compactness of interpretability logic.
Department of Mathematics, University of Osijek
2004
text
info:eu-repo/semantics/article
info:eu-repo/semantics/publishedVersion
application/pdf
https://hrcak.srce.hr/722
https://hrcak.srce.hr/file/1438
Mathematical Communications
ISSN 1331-0623 (Print)
ISSN 1848-8013 (Online)
Volume 9
Issue 1
eng
info:eu-repo/semantics/openAccess
The full text of articles published in this journal can be used free of charge for personal and educational purposes while respecting authors' and publisher's copyrights. Annual subscription to printed copies is USD 50.00. Members of the Osijek Mathematical Society and the Mathematical Club of the Department of Mathematics receive this journal free of charge.
oai:hrcak.srce.hr:724
2008-06-03
journal:39
Estimating convexifiers in continuous optimization
Zlobec, S.
twice continuously differentiable function; convexifier; nonlinear programming; convex model; system of nonlinear equations
Every function of several variables with the continuous second
derivative can be convexified (i.e., made convex) by adding to it a
quadratic "convexifier". In this paper we give simple estimates on the
bounds of convexifiers. Using the idea of convexification, many problems in applied mathematics can be reduced to convex mathematical programming models. This is illustrated here for nonlinear programs and systems of nonlinear equations.
Department of Mathematics, University of Osijek
2003
text
info:eu-repo/semantics/article
info:eu-repo/semantics/publishedVersion
application/pdf
https://hrcak.srce.hr/724
https://hrcak.srce.hr/file/1441
Mathematical Communications
ISSN 1331-0623 (Print)
ISSN 1848-8013 (Online)
Volume 8
Issue 2
eng
info:eu-repo/semantics/openAccess
The full text of articles published in this journal can be used free of charge for personal and educational purposes while respecting authors' and publisher's copyrights. Annual subscription to printed copies is USD 50.00. Members of the Osijek Mathematical Society and the Mathematical Club of the Department of Mathematics receive this journal free of charge.
oai:hrcak.srce.hr:725
2008-06-03
journal:39
Mann-Ishikawa iterations and Mann-Ishikawa iterations with errors are equivalent models
Şolutuz, Ş. M.
Mann-Ishikawa iterations; Mann-Ishikawa iterations with errors
Mann-Ishikawa iterations and Mann-Ishikawa iterations with errors are
equivalent models for several classes of operators.
Department of Mathematics, University of Osijek
2003
text
info:eu-repo/semantics/article
info:eu-repo/semantics/publishedVersion
application/pdf
https://hrcak.srce.hr/725
https://hrcak.srce.hr/file/1442
Mathematical Communications
ISSN 1331-0623 (Print)
ISSN 1848-8013 (Online)
Volume 8
Issue 2
eng
info:eu-repo/semantics/openAccess
The full text of articles published in this journal can be used free of charge for personal and educational purposes while respecting authors' and publisher's copyrights. Annual subscription to printed copies is USD 50.00. Members of the Osijek Mathematical Society and the Mathematical Club of the Department of Mathematics receive this journal free of charge.
oai:hrcak.srce.hr:726
2008-06-03
journal:39
Further results on I-limit superior and limit inferior
Lahiri, B. K.
Das, P.
ideal; filter; I-limit superior and I-limit inferior; I-convergence; I-boundedness of a sequence
In this paper we obtain (after the works of Demirci) some further properties of I-limit superior and I-limit inferior and obtain the I-analogue of Cauchy criterion of convergence of a sequence of real numbers.
Department of Mathematics, University of Osijek
2003
text
info:eu-repo/semantics/article
info:eu-repo/semantics/publishedVersion
application/pdf
https://hrcak.srce.hr/726
https://hrcak.srce.hr/file/1443
Mathematical Communications
ISSN 1331-0623 (Print)
ISSN 1848-8013 (Online)
Volume 8
Issue 2
eng
info:eu-repo/semantics/openAccess
The full text of articles published in this journal can be used free of charge for personal and educational purposes while respecting authors' and publisher's copyrights. Annual subscription to printed copies is USD 50.00. Members of the Osijek Mathematical Society and the Mathematical Club of the Department of Mathematics receive this journal free of charge.
oai:hrcak.srce.hr:727
2008-06-03
journal:39
Approximating negative and harmonic mean moments for the Poisson distribution
Jones, C. M.
Poisson distribution; negative moments; Poisson-Charlie polynomials; harmonic mean; multi-centre clinical trials
Asymptotic expansions and the related approximations are
constructed for the negative moments of the Poisson distribution
and the moments of the harmonic mean of independent and
identically distributed (i.i.d.) Poisson random variable (r.v.). The
accuracy of the approximations are assessed and applications to
multi-centre clinical trials are outlined.
Department of Mathematics, University of Osijek
2003
text
info:eu-repo/semantics/article
info:eu-repo/semantics/publishedVersion
application/pdf
https://hrcak.srce.hr/727
https://hrcak.srce.hr/file/1444
Mathematical Communications
ISSN 1331-0623 (Print)
ISSN 1848-8013 (Online)
Volume 8
Issue 2
eng
info:eu-repo/semantics/openAccess
The full text of articles published in this journal can be used free of charge for personal and educational purposes while respecting authors' and publisher's copyrights. Annual subscription to printed copies is USD 50.00. Members of the Osijek Mathematical Society and the Mathematical Club of the Department of Mathematics receive this journal free of charge.
oai:hrcak.srce.hr:728
2008-06-03
journal:39
More on unicoherence at subcontinua
Charatonik, J. J.
Puga, I.
component; continuum; locally connected; unicoherence; nicoherence at a subcontinuum
Studies are continued of unicoherence of a continuum X at
its subcontinuum Y. Relations are analyzed between unicoherence of X at Y, unicoherence of either X or Y, and structure of components of the complement X Y. The obtained results generalize certain teorems
proved in cite [OP]. Further, it is shown that terminality of Y implies
unicoherence of X at Y. Applications are shown of this result to
compactifications of a ray.
Department of Mathematics, University of Osijek
2003
text
info:eu-repo/semantics/article
info:eu-repo/semantics/publishedVersion
application/pdf
https://hrcak.srce.hr/728
https://hrcak.srce.hr/file/1445
Mathematical Communications
ISSN 1331-0623 (Print)
ISSN 1848-8013 (Online)
Volume 8
Issue 2
eng
info:eu-repo/semantics/openAccess
The full text of articles published in this journal can be used free of charge for personal and educational purposes while respecting authors' and publisher's copyrights. Annual subscription to printed copies is USD 50.00. Members of the Osijek Mathematical Society and the Mathematical Club of the Department of Mathematics receive this journal free of charge.
oai:hrcak.srce.hr:729
2008-06-03
journal:39
On a theorem of S.S.Bhatia and B.Ram
Tomovski, Ž.
Dirichlet kernel; Fejer kernel; L^1-convergence; complex trigonometric series; Bernstein's inequality
In this paper some inequalities for Dirichlet's and Fejer's kernels
proved in [6] are refined and extended.
Then we have obtained the conditions for L^1-convergence of the
r-th derivatives of complex trigonometric series.
These results are extensions of corresponding Bhatia's and Ram's
results for complex trigonometric series (case r=0).
Department of Mathematics, University of Osijek
2003
text
info:eu-repo/semantics/article
info:eu-repo/semantics/publishedVersion
application/pdf
https://hrcak.srce.hr/729
https://hrcak.srce.hr/file/1446
Mathematical Communications
ISSN 1331-0623 (Print)
ISSN 1848-8013 (Online)
Volume 8
Issue 2
eng
info:eu-repo/semantics/openAccess
The full text of articles published in this journal can be used free of charge for personal and educational purposes while respecting authors' and publisher's copyrights. Annual subscription to printed copies is USD 50.00. Members of the Osijek Mathematical Society and the Mathematical Club of the Department of Mathematics receive this journal free of charge.
oai:hrcak.srce.hr:730
2008-06-03
journal:39
On the number of solutions of the Diophantine equation of Frobenius - General case
Komatsu, T.
Diophantine problem of Frobenius; number of solutions
We determine the number of solutions of the equation $a_1 x_1+a_2
x_2+cdots+a_m x_m=b$ in non-negative integers $x_1$, $x_2$,
$dots$, $x_n$. If $m=2$, then the largest $b$ for which no
solution exists is $a_1 a_2-a_1-a_2$, and an explicit formula for
the number of solutions is known. In this paper we give the method
for computing the desired number. The method is illustrated with
several examples.
Department of Mathematics, University of Osijek
2003
text
info:eu-repo/semantics/article
info:eu-repo/semantics/publishedVersion
application/pdf
https://hrcak.srce.hr/730
https://hrcak.srce.hr/file/1447
Mathematical Communications
ISSN 1331-0623 (Print)
ISSN 1848-8013 (Online)
Volume 8
Issue 2
eng
info:eu-repo/semantics/openAccess
The full text of articles published in this journal can be used free of charge for personal and educational purposes while respecting authors' and publisher's copyrights. Annual subscription to printed copies is USD 50.00. Members of the Osijek Mathematical Society and the Mathematical Club of the Department of Mathematics receive this journal free of charge.
oai:hrcak.srce.hr:731
2008-06-03
journal:39
The properties of spaces which admit a Whitney map
Lončar, I.
Hyperspace; Whitney map
Let X be a topological space and 2^{X} the hyperspace of closed subsets of X. It is known that there is a Whitney map on the hyperspace 2^{X} for separable metric spaces X. In this paper we study the properties of spaces which admit a Whitney map for some subspaces of 2^{X}. We shall show that, under some natural assumptions, such spaces are closely related to separable
metric spaces.
Department of Mathematics, University of Osijek
2003
text
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info:eu-repo/semantics/publishedVersion
application/pdf
https://hrcak.srce.hr/731
https://hrcak.srce.hr/file/1448
Mathematical Communications
ISSN 1331-0623 (Print)
ISSN 1848-8013 (Online)
Volume 8
Issue 2
eng
info:eu-repo/semantics/openAccess
The full text of articles published in this journal can be used free of charge for personal and educational purposes while respecting authors' and publisher's copyrights. Annual subscription to printed copies is USD 50.00. Members of the Osijek Mathematical Society and the Mathematical Club of the Department of Mathematics receive this journal free of charge.
oai:hrcak.srce.hr:732
2008-06-03
journal:39
DGS-trapezoids in GS-quasigroups
Kolar-Begović, Z.
Volenec, V.
GS-quasigroup; DGS-trapezoid
The concept of the DGS-trapezoid is defined and investigated in any GS-quasigroup and geometrical interpretation in the GS-quasigroup $C( frac{1}{2}(1+sqrt 5 ))$ is also given. The connection of this concept with GS-trapezoids in the general GS-quasigroup is obtained.
Department of Mathematics, University of Osijek
2003
text
info:eu-repo/semantics/article
info:eu-repo/semantics/publishedVersion
application/pdf
https://hrcak.srce.hr/732
https://hrcak.srce.hr/file/1449
Mathematical Communications
ISSN 1331-0623 (Print)
ISSN 1848-8013 (Online)
Volume 8
Issue 2
eng
info:eu-repo/semantics/openAccess
The full text of articles published in this journal can be used free of charge for personal and educational purposes while respecting authors' and publisher's copyrights. Annual subscription to printed copies is USD 50.00. Members of the Osijek Mathematical Society and the Mathematical Club of the Department of Mathematics receive this journal free of charge.
oai:hrcak.srce.hr:734
2008-06-03
journal:39
On the Ishikawa iterative approximation with mixed errors for solutions to variational inclusions with accretive type mappings in Banach spaces
Feng, G.
variational inclusion;accretive mapping; Ishikawa iterative sequence with mixed errors; Mann iterative sequence with mixed errors
Using the new analysis techniques, the existence and iterative approximation problem of a solution for a class of nonlinear
variational inclusions with accretive type mappings are discussed in arbitrary Banach spaces. The results extend and improve some recent
results.
Department of Mathematics, University of Osijek
2003
text
info:eu-repo/semantics/article
info:eu-repo/semantics/publishedVersion
application/pdf
https://hrcak.srce.hr/734
https://hrcak.srce.hr/file/1452
Mathematical Communications
ISSN 1331-0623 (Print)
ISSN 1848-8013 (Online)
Volume 8
Issue 1
eng
info:eu-repo/semantics/openAccess
The full text of articles published in this journal can be used free of charge for personal and educational purposes while respecting authors' and publisher's copyrights. Annual subscription to printed copies is USD 50.00. Members of the Osijek Mathematical Society and the Mathematical Club of the Department of Mathematics receive this journal free of charge.
oai:hrcak.srce.hr:736
2008-06-03
journal:39
A relation among DS^{2}, TS^{2} and non-cylindrical ruled surfaces
Karakaş, B.
Gündoğan, H.
dual unit sphere; non-cylindrical ruled surface; spherical curve; anti-symmetric linear vector field; tangent bundle
$TS^{2}$ is a differentiable manifold of dimension 4. For every $%
Xin TS^{2}$, if we set $X=(p,x)$ we have $<vec{p},vec{x}>=0$ since $vec{p}$ is orthogonal to $T_{p}S^{2}$, therefore $parallel vec{p}parallel =1$. Those there could exist a one-to-one correspondence between $TS^{2}$ and $DS^{2}$. In this paper we gave and studied a one-to-one correspondence among $TS^{2}$, $DS^{2}$ and a non cylindrical ruled surface. We showed that
for a restriction of an anti-symmetric linear vector field A along a
spherical curve $alpha (t)$ there exists a non-cylindrical ruled surface
which corresponds to $alpha (t)$ and has the following prametrization [alpha (t,lambda )=alpha (vec{t})+A(alpha (t))+lambda alpha (vec{t})]
So it is possible to study non-cylindrical ruled surfaces as the set of $
(alpha (t),A(alpha (t)))$, where $alpha (t)in S^{2}$ and $A$ is an
anti-symmetric linear vector field in ${cal R}^{3}$.
Department of Mathematics, University of Osijek
2003
text
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info:eu-repo/semantics/publishedVersion
application/pdf
https://hrcak.srce.hr/736
https://hrcak.srce.hr/file/1455
Mathematical Communications
ISSN 1331-0623 (Print)
ISSN 1848-8013 (Online)
Volume 8
Issue 1
eng
info:eu-repo/semantics/openAccess
The full text of articles published in this journal can be used free of charge for personal and educational purposes while respecting authors' and publisher's copyrights. Annual subscription to printed copies is USD 50.00. Members of the Osijek Mathematical Society and the Mathematical Club of the Department of Mathematics receive this journal free of charge.
oai:hrcak.srce.hr:737
2008-06-03
journal:39
An equivalence between the convergences of Ishikawa, Mann and Picard iterations
Şolutuz, Ş. M.
Picard iteration; Ishikawa iteration; Mann iteration; Ishikawa type iteration; Mann type iteration; contractive map; asymptotic nonexpansive map
We will show that the convergence of Picard iteration is equivalent to the convergence of Mann and Ishikawa iterations, when the operator is a contraction and aymptotic nonexpansive.
Department of Mathematics, University of Osijek
2003
text
info:eu-repo/semantics/article
info:eu-repo/semantics/publishedVersion
application/pdf
https://hrcak.srce.hr/737
https://hrcak.srce.hr/file/1456
Mathematical Communications
ISSN 1331-0623 (Print)
ISSN 1848-8013 (Online)
Volume 8
Issue 1
eng
info:eu-repo/semantics/openAccess
The full text of articles published in this journal can be used free of charge for personal and educational purposes while respecting authors' and publisher's copyrights. Annual subscription to printed copies is USD 50.00. Members of the Osijek Mathematical Society and the Mathematical Club of the Department of Mathematics receive this journal free of charge.
oai:hrcak.srce.hr:739
2008-06-03
journal:39
Interval method for interval linear program
Viher, R.
interval method; interval linear program; first form of interval linear program; second form of interval linear program; explicit solution; sensitivity analyses
In the problem of interval linear programming (ref{ijedan})
begin{equation}label{ijedan}
begin{array}{c}
max c^{T}x\
aleq Axleq b
end{array}
end{equation}
$x,cinmathbf{R}^{n}$; $a,binmathbf{R}^{m}$; $Ainmathbf{R}_{m}^{mtimes n}$ ($A$ is of full row
rank) we introduce the new variable $t=c_{1}x_{1}+cdots+c_{k}x_{k}+cdots+c_{n}x_{n}$ and eliminate
the old variable $(c_{k}neq 0)$
[x_{k}=frac{1}{c_{k}}t-frac{c_{1}}{c_{k}}x_{1}-cdots-frac{c_{k-1}}{c_{k}}x_{k-1}-
frac{c_{k+1}}{c_{k}}x_{k+1}-cdots-frac{c_{n}}{c_{k}}x_{n}.]
So we come to the second form
begin{equation}label{idva}
begin{array}{c}
max t\
a+thleq Bx'leq b+th
end{array}
end{equation}
$x'inmathbf{R}^{n-1}$; $a,b,hinmathbf{R}^{m}$; $Binmathbf{R}_{m-1}^{mtimes (n-1)}$. It is known
when $cinmathcal{R}(A^{T})$ that problem (ref{ijedan}) has an explicit solution. In this article we formulate
the analogous theorem for the second form (ref{idva}), and then show the application of those results on the
problem of sensitivity analyses.
Department of Mathematics, University of Osijek
2003
text
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info:eu-repo/semantics/publishedVersion
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https://hrcak.srce.hr/739
https://hrcak.srce.hr/file/1459
Mathematical Communications
ISSN 1331-0623 (Print)
ISSN 1848-8013 (Online)
Volume 8
Issue 1
eng
info:eu-repo/semantics/openAccess
The full text of articles published in this journal can be used free of charge for personal and educational purposes while respecting authors' and publisher's copyrights. Annual subscription to printed copies is USD 50.00. Members of the Osijek Mathematical Society and the Mathematical Club of the Department of Mathematics receive this journal free of charge.
oai:hrcak.srce.hr:741
2008-06-03
journal:39
Lines with the butterfly property
Čerin, Z.
butterfly property; line; conic; inscribed quadrangle; midpoint
In this paper it is explored which lines have the butterfly property with respect to quadrangles (inscribed into a given conic curve).
Department of Mathematics, University of Osijek
2003
text
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https://hrcak.srce.hr/741
https://hrcak.srce.hr/file/1462
Mathematical Communications
ISSN 1331-0623 (Print)
ISSN 1848-8013 (Online)
Volume 8
Issue 1
eng
info:eu-repo/semantics/openAccess
The full text of articles published in this journal can be used free of charge for personal and educational purposes while respecting authors' and publisher's copyrights. Annual subscription to printed copies is USD 50.00. Members of the Osijek Mathematical Society and the Mathematical Club of the Department of Mathematics receive this journal free of charge.
oai:hrcak.srce.hr:742
2008-06-03
journal:39
Ishikawa iterative process for strongly pseudocontractive operators in arbitrary Banach spaces
Ćirić, Lj.
Ume, J. S.
Ishikawa iteration process; strongly pseudocontractive operator
In this note we give a correction to the main result of Zhou in [14] on the convergence of the Ishikawa iteration process to a unique fixed point of a strongly pseudocontractive operator in arbitrary real Banach spaces. Our results extend the recent result of Soltuz [11] to arbitrary strongly pseudocontractive operators.
Department of Mathematics, University of Osijek
2003
text
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info:eu-repo/semantics/publishedVersion
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https://hrcak.srce.hr/742
https://hrcak.srce.hr/file/1463
Mathematical Communications
ISSN 1331-0623 (Print)
ISSN 1848-8013 (Online)
Volume 8
Issue 1
eng
info:eu-repo/semantics/openAccess
The full text of articles published in this journal can be used free of charge for personal and educational purposes while respecting authors' and publisher's copyrights. Annual subscription to printed copies is USD 50.00. Members of the Osijek Mathematical Society and the Mathematical Club of the Department of Mathematics receive this journal free of charge.
oai:hrcak.srce.hr:745
2008-06-03
journal:39
Weakly Picard pairs of some multivalued operators
Sîntărian, A.
fixed point; common fixed point; weakly Picard multivalued operator; weakly Picard pair of multivalued operators
The purpose of this paper is to present a partial answer to the
following problem:
Let (X,d) be a metric space and $T_1,T_2:Xto P(X)$ two
multivalued operators. Determine the metric conditions which
imply that (T_1,T_2) is a weakly Picard pair of multivalued operators and T_1, T_2 are weakly Picard multivalued operators.
Department of Mathematics, University of Osijek
2003
text
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https://hrcak.srce.hr/745
https://hrcak.srce.hr/file/1467
Mathematical Communications
ISSN 1331-0623 (Print)
ISSN 1848-8013 (Online)
Volume 8
Issue 1
eng
info:eu-repo/semantics/openAccess
The full text of articles published in this journal can be used free of charge for personal and educational purposes while respecting authors' and publisher's copyrights. Annual subscription to printed copies is USD 50.00. Members of the Osijek Mathematical Society and the Mathematical Club of the Department of Mathematics receive this journal free of charge.
oai:hrcak.srce.hr:749
2008-06-03
journal:39
Metrical relations in barycentric coordinates
Volenec, V.
barycentric coordinates
Let Δ be the area of the fundamental triangle ABC of barycentric coordinates and α=cot A,β =cot B, γ=cot C. The vectors $boldsymbol{v}_i=[x_{i},y_{i},z_{i}]$ $(i=1,2)$ have the scalar product $2Delta (alpha x_{1}x_{2}+beta y_{1}y_{2}+gamma z_{1}z_{2})$. This fact implies all important formulas about metrical relations of points and lines. The main and probably new results are Theorems 1 and 8.
Department of Mathematics, University of Osijek
2003
text
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https://hrcak.srce.hr/749
https://hrcak.srce.hr/file/1473
Mathematical Communications
ISSN 1331-0623 (Print)
ISSN 1848-8013 (Online)
Volume 8
Issue 1
eng
info:eu-repo/semantics/openAccess
The full text of articles published in this journal can be used free of charge for personal and educational purposes while respecting authors' and publisher's copyrights. Annual subscription to printed copies is USD 50.00. Members of the Osijek Mathematical Society and the Mathematical Club of the Department of Mathematics receive this journal free of charge.
oai:hrcak.srce.hr:760
2008-06-03
journal:39
Identifying spatial point sets
Späth, H.
computational metrology; unknown rotation; unknown translation; identifying spatial point sets
Two sets of spatial points are checked whether they can pproximately be transformed into each other by applying some unknown translation and some unknown rotation. This problem occurs at least in two dimensions within computational metrology. Numerical methods for two types of objective functions (weighted sum of squared distances and sum of distances) are developed and numerical examples are given.
Department of Mathematics, University of Osijek
2003
text
info:eu-repo/semantics/article
info:eu-repo/semantics/publishedVersion
application/pdf
https://hrcak.srce.hr/760
https://hrcak.srce.hr/file/1488
Mathematical Communications
ISSN 1331-0623 (Print)
ISSN 1848-8013 (Online)
Volume 8
Issue 1
eng
info:eu-repo/semantics/openAccess
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oai:hrcak.srce.hr:761
2008-06-03
journal:39
On some linear positive operators in exponential weighted spaces
Walczak, Z.
Szasz-Mirakyan operator; exponential weighted space; degree of approximation
We consider certain linear positive operators in exponential weighted spaces of functions of one variable and we study approximation properties of these operators. We give theorems on the degree of approximation of functions from exponential weighted spaces by introduced operators, using norms of these spaces.
Department of Mathematics, University of Osijek
2003
text
info:eu-repo/semantics/article
info:eu-repo/semantics/publishedVersion
application/x-tex
https://hrcak.srce.hr/761
https://hrcak.srce.hr/file/1489
Mathematical Communications
ISSN 1331-0623 (Print)
ISSN 1848-8013 (Online)
Volume 8
Issue 1
eng
info:eu-repo/semantics/openAccess
The full text of articles published in this journal can be used free of charge for personal and educational purposes while respecting authors' and publisher's copyrights. Annual subscription to printed copies is USD 50.00. Members of the Osijek Mathematical Society and the Mathematical Club of the Department of Mathematics receive this journal free of charge.
oai:hrcak.srce.hr:763
2008-06-03
journal:39
A-statistical approximation by Jayasri operators
İspir, N.
A-statistical convergence;positive linear operators; approximation; degree of approximation; Korovkin type theorem
In this study we investigate the A- statistical approximation properties of a sequence of the Jayasri operators. Also we consider the degree of the A-statistical approximation of the sequence of these operators.
Department of Mathematics, University of Osijek
2003
text
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info:eu-repo/semantics/publishedVersion
application/pdf
https://hrcak.srce.hr/763
https://hrcak.srce.hr/file/1493
Mathematical Communications
ISSN 1331-0623 (Print)
ISSN 1848-8013 (Online)
Volume 8
Issue 1
eng
info:eu-repo/semantics/openAccess
The full text of articles published in this journal can be used free of charge for personal and educational purposes while respecting authors' and publisher's copyrights. Annual subscription to printed copies is USD 50.00. Members of the Osijek Mathematical Society and the Mathematical Club of the Department of Mathematics receive this journal free of charge.
oai:hrcak.srce.hr:764
2008-06-03
journal:39
Δ-statistical and strong Δ-Cesaro convergence of sequences of fuzzy numbers
Bilgin, T.
fuzzy number; Δ-statistical convergence, strong Δ-summability
In this paper we introduce and study the concepts of strongly
Δ -summable and Δ-statistical convergence of sequences of fuzzy
numbers.
Department of Mathematics, University of Osijek
2003
text
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info:eu-repo/semantics/publishedVersion
application/x-tex
https://hrcak.srce.hr/764
https://hrcak.srce.hr/file/1494
Mathematical Communications
ISSN 1331-0623 (Print)
ISSN 1848-8013 (Online)
Volume 8
Issue 1
eng
info:eu-repo/semantics/openAccess
The full text of articles published in this journal can be used free of charge for personal and educational purposes while respecting authors' and publisher's copyrights. Annual subscription to printed copies is USD 50.00. Members of the Osijek Mathematical Society and the Mathematical Club of the Department of Mathematics receive this journal free of charge.
oai:hrcak.srce.hr:765
2008-06-03
journal:39
Classification of quadrics in a double isotropic space
Beban-Brkić, J.
quadrics; plane isotropic geometry; geometry of the double isotropic space
This paper gives the classification of second order surfaces in a double isotropic space $I_{3}^{(2)}$. Although quadrics in $I_{3}^{(2)}$ have been investigated earlier [e.g. 8 or 9], this paper offers a new method based on linear algebra. The definition of invariants of a quadric with respect to the group of motions in $I_{3}^{(2)}$ makes it possible to determine the type of a quadric without reducing its equation to a canonical form. For that purpose isometric properties of conics in the isotropic plane and affine properties of quadrics are used.
Department of Mathematics, University of Osijek
2003
text
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info:eu-repo/semantics/publishedVersion
application/pdf
https://hrcak.srce.hr/765
https://hrcak.srce.hr/file/1495
Mathematical Communications
ISSN 1331-0623 (Print)
ISSN 1848-8013 (Online)
Volume 8
Issue 1
eng
info:eu-repo/semantics/openAccess
The full text of articles published in this journal can be used free of charge for personal and educational purposes while respecting authors' and publisher's copyrights. Annual subscription to printed copies is USD 50.00. Members of the Osijek Mathematical Society and the Mathematical Club of the Department of Mathematics receive this journal free of charge.
oai:hrcak.srce.hr:767
2008-06-03
journal:39
Fixed points of fuzzy mappings in Hilbert spaces
Dutta, P. N.
Choudhury, B. S.
fuzzy mapping; Hilbert space; fixed point; approximate quantity
In this paper we work out two fixed point theorems for fuzzy mappings on Hilbert spaces. The proofs rely on the paralellogram law in Hilbert spaces.
Department of Mathematics, University of Osijek
2002
text
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info:eu-repo/semantics/publishedVersion
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https://hrcak.srce.hr/767
https://hrcak.srce.hr/file/1498
Mathematical Communications
ISSN 1331-0623 (Print)
ISSN 1848-8013 (Online)
Volume 7
Issue 2
eng
info:eu-repo/semantics/openAccess
The full text of articles published in this journal can be used free of charge for personal and educational purposes while respecting authors' and publisher's copyrights. Annual subscription to printed copies is USD 50.00. Members of the Osijek Mathematical Society and the Mathematical Club of the Department of Mathematics receive this journal free of charge.
oai:hrcak.srce.hr:768
2008-06-03
journal:39
On mapping properties and the property of Kelley
Charatonik, J. J.
confluent; continuum; hereditarily; homogeneous; property of Kelley; weakly confluent
Mapping conditions are studied under which a continuum
having the property of Kelley has this property hereditarily. The obtained results, related mainly to confluent mappings, extend some known assertions of the subject.
Department of Mathematics, University of Osijek
2002
text
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info:eu-repo/semantics/publishedVersion
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https://hrcak.srce.hr/768
https://hrcak.srce.hr/file/1499
Mathematical Communications
ISSN 1331-0623 (Print)
ISSN 1848-8013 (Online)
Volume 7
Issue 2
eng
info:eu-repo/semantics/openAccess
The full text of articles published in this journal can be used free of charge for personal and educational purposes while respecting authors' and publisher's copyrights. Annual subscription to printed copies is USD 50.00. Members of the Osijek Mathematical Society and the Mathematical Club of the Department of Mathematics receive this journal free of charge.
oai:hrcak.srce.hr:769
2008-06-03
journal:39
On completely equidistributed numbers
Limić, N.
equidistributed numbers; pseudo-random numbers
We analyzed a new method for proving equidistribution of numbers. The proposed method is simple and can be used to prove equidistribution of all known classes of numbers such
as Weyl's numbers and Koksma's numbers. Emphasis of this approach is put on the complete equidistribution of numbers and a non-trivial result in this direction is obtained.
Department of Mathematics, University of Osijek
2002
text
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info:eu-repo/semantics/publishedVersion
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https://hrcak.srce.hr/769
https://hrcak.srce.hr/file/1500
Mathematical Communications
ISSN 1331-0623 (Print)
ISSN 1848-8013 (Online)
Volume 7
Issue 2
eng
info:eu-repo/semantics/openAccess
The full text of articles published in this journal can be used free of charge for personal and educational purposes while respecting authors' and publisher's copyrights. Annual subscription to printed copies is USD 50.00. Members of the Osijek Mathematical Society and the Mathematical Club of the Department of Mathematics receive this journal free of charge.
oai:hrcak.srce.hr:770
2008-06-03
journal:39
Some convergence theorems of implicit iterative process for nonexpansive mappings in Banach spaces
Liu, J. A.
implicit iteration process; finite family of nonexpansive mappings; common fixed point
The purpose of this paper is to study the convergence problem of
implicit iteration process for a finite family of nonexpansive mappings
in Banach spaces. The results presented in this paper not only
generalize some recent results but also give an affirmative answer to the open question suggested by Xu and Ori [11].
Department of Mathematics, University of Osijek
2002
text
info:eu-repo/semantics/article
info:eu-repo/semantics/publishedVersion
application/pdf
https://hrcak.srce.hr/770
https://hrcak.srce.hr/file/1501
Mathematical Communications
ISSN 1331-0623 (Print)
ISSN 1848-8013 (Online)
Volume 7
Issue 2
eng
info:eu-repo/semantics/openAccess
The full text of articles published in this journal can be used free of charge for personal and educational purposes while respecting authors' and publisher's copyrights. Annual subscription to printed copies is USD 50.00. Members of the Osijek Mathematical Society and the Mathematical Club of the Department of Mathematics receive this journal free of charge.
oai:hrcak.srce.hr:771
2008-06-03
journal:39
On the theorem of N. Singh and K. M. Sharma
Tomovski, Ž.
quasi-convex sequence; Moore's class; L^1-convergence of Fourier series
A new short proof of the Theorem of N. Singh and K. M. Sharma (see [7]) is given.
Department of Mathematics, University of Osijek
2002
text
info:eu-repo/semantics/article
info:eu-repo/semantics/publishedVersion
application/pdf
https://hrcak.srce.hr/771
https://hrcak.srce.hr/file/1502
Mathematical Communications
ISSN 1331-0623 (Print)
ISSN 1848-8013 (Online)
Volume 7
Issue 2
eng
info:eu-repo/semantics/openAccess
The full text of articles published in this journal can be used free of charge for personal and educational purposes while respecting authors' and publisher's copyrights. Annual subscription to printed copies is USD 50.00. Members of the Osijek Mathematical Society and the Mathematical Club of the Department of Mathematics receive this journal free of charge.
oai:hrcak.srce.hr:772
2008-06-03
journal:39
Factorizations of the complete graphs into factor of subdiameter two and factors of diameter three
Vukičević, D.
factorization; decomposition; graph
We search for the minimal number of vertices of the complete graph that can be decomposed into one factor of subdiameter 2 and k factors of diameter 3. We find as follows: exact values for k≤3, upper and lower bounds for small values of k and
[lim_{krightarrow infty }frac{phi left( kright) }{k}=2.]
Department of Mathematics, University of Osijek
2002
text
info:eu-repo/semantics/article
info:eu-repo/semantics/publishedVersion
application/pdf
https://hrcak.srce.hr/772
https://hrcak.srce.hr/file/1503
Mathematical Communications
ISSN 1331-0623 (Print)
ISSN 1848-8013 (Online)
Volume 7
Issue 2
eng
info:eu-repo/semantics/openAccess
The full text of articles published in this journal can be used free of charge for personal and educational purposes while respecting authors' and publisher's copyrights. Annual subscription to printed copies is USD 50.00. Members of the Osijek Mathematical Society and the Mathematical Club of the Department of Mathematics receive this journal free of charge.
oai:hrcak.srce.hr:773
2008-06-03
journal:39
GS-trapezoids in GS-quasigroups
Volenec, V.
Kolar, Z.
GS-quasigroup; GS-trapezoid
In this paper the concept of a GS-trapezoid in a GS-quasigroup is defined and some characterizations of that are proved and geometrical representation of the properties of the quaternary relation GST in the GS-quasigroup $C(frac{1}{2}(1+sqrt{5}))$ is given.
Department of Mathematics, University of Osijek
2002
text
info:eu-repo/semantics/article
info:eu-repo/semantics/publishedVersion
application/pdf
https://hrcak.srce.hr/773
https://hrcak.srce.hr/file/1504
Mathematical Communications
ISSN 1331-0623 (Print)
ISSN 1848-8013 (Online)
Volume 7
Issue 2
eng
info:eu-repo/semantics/openAccess
The full text of articles published in this journal can be used free of charge for personal and educational purposes while respecting authors' and publisher's copyrights. Annual subscription to printed copies is USD 50.00. Members of the Osijek Mathematical Society and the Mathematical Club of the Department of Mathematics receive this journal free of charge.
oai:hrcak.srce.hr:774
2008-06-03
journal:39
Scaling laws for fractional Volterra equations with chi-square random data
Anh, V. V.
Leonenko, N. N.
Melnikova, O. O.
fractional integro-differential equation; fractional diffusion-wave equation; chi-square subordination; Mittag-Leffler function; spectral representation; long-range dependence
This paper presents Gaussian and non-Gaussian scenarios for the renormalized solutions of fractional integro-differential equations of Volterra type. The solutions are obtained under random initial conditions which are subordinated to chi-square random fields with weak or strong dependence.
Department of Mathematics, University of Osijek
2002
text
info:eu-repo/semantics/article
info:eu-repo/semantics/publishedVersion
application/pdf
https://hrcak.srce.hr/774
https://hrcak.srce.hr/file/1505
Mathematical Communications
ISSN 1331-0623 (Print)
ISSN 1848-8013 (Online)
Volume 7
Issue 2
eng
info:eu-repo/semantics/openAccess
The full text of articles published in this journal can be used free of charge for personal and educational purposes while respecting authors' and publisher's copyrights. Annual subscription to printed copies is USD 50.00. Members of the Osijek Mathematical Society and the Mathematical Club of the Department of Mathematics receive this journal free of charge.
oai:hrcak.srce.hr:775
2008-06-03
journal:39
On a class of module maps of Hilbert C*-modules
Bakić, D.
Guljaš, B.
C*-algebra; Hilbert C*-module; adjointable operator
The paper describes some basic properties of a class of module maps of Hilbert C*-modules.
In Section 1 ideal submodules are considered and the canonical Hilbert C*-module structure on the quotient of a Hilbert C*-module over an ideal submodule is described.
Given a Hilbert C*-module V, an ideal submodule $V_{inss}$, and the quotient $V/V_{inss}$, canonical morphisms of the corresponding C*-algebras of adjointable operators are discussed.
In the second part of the paper a class of module maps of Hilbert C*-modules is introduced.Given Hilbert C*-modules V and W and a morphism $varphi : ass rightarrow bss$ of the underlying cez-algebras, a map $Phi : V rightarrow W$ belongs to the class under consideration if it preserves inner products modulo $varphi$: $langle Phi(x), Phi(y) rangle = varphi(langle x,y rangle)$ for all $x,y in V$.
It is shown that each morphism Φ of this kind is necessarily a contraction such that the kernel of Φ is an ideal submodule of V. A related class of morphisms of the corresponding linking algebras is also discussed.
Department of Mathematics, University of Osijek
2002
text
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info:eu-repo/semantics/publishedVersion
application/pdf
https://hrcak.srce.hr/775
https://hrcak.srce.hr/file/1506
Mathematical Communications
ISSN 1331-0623 (Print)
ISSN 1848-8013 (Online)
Volume 7
Issue 2
eng
info:eu-repo/semantics/openAccess
The full text of articles published in this journal can be used free of charge for personal and educational purposes while respecting authors' and publisher's copyrights. Annual subscription to printed copies is USD 50.00. Members of the Osijek Mathematical Society and the Mathematical Club of the Department of Mathematics receive this journal free of charge.
oai:hrcak.srce.hr:776
2008-06-03
journal:39
Network cost allocation games based on threshold discounting
Skorin-Kapov, D.
network design; economies of scale; heuristic algorithms; combinatorial optimization; cost allocation; cooperative games
Consider networks in which each pair of nodes needs to communicate. The communication flow between any pair of nodes can be delivered through a direct link or via some connecting path in the network. By discounting the cost of flow through links for which the high flow volume is anticipated, network designers exploit economies of scale. This approach encourages the concentration of flows and use of relatively small number of links. This led to the design of well known hub networks and more recently hub-like networks.
Applications include telecommunications, airline traffic flow, and mail
delivery networks. The cost of services delivered through such networks is distributed among its users who may be individuals or organizations with possibly conflicting interests. The cooperation of these users is essential for the exploitation of economies of scale. Consequently, there is a need to find a fair distribution of the cost of providing the service among network users. In this paper, we present a survey of some recent results in the development of cooperative game theory based mechanisms to efficiently characterize cost allocation solutions for hub and hub-like networks.
Specifically, we formulate the associated hub and hub-like network cost allocation games. Then, while paying special attention to users' contribution to economies of scale, we demonstrate that some attractive cost allocation solutions, which provide users with the incentive to cooperate, can be efficiently computed.
Department of Mathematics, University of Osijek
2002
text
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info:eu-repo/semantics/publishedVersion
application/pdf
https://hrcak.srce.hr/776
https://hrcak.srce.hr/file/1507
Mathematical Communications
ISSN 1331-0623 (Print)
ISSN 1848-8013 (Online)
Volume 7
Issue 1
eng
info:eu-repo/semantics/openAccess
The full text of articles published in this journal can be used free of charge for personal and educational purposes while respecting authors' and publisher's copyrights. Annual subscription to printed copies is USD 50.00. Members of the Osijek Mathematical Society and the Mathematical Club of the Department of Mathematics receive this journal free of charge.
oai:hrcak.srce.hr:778
2008-06-03
journal:39
On some subspaces of an FK-space
Dağadur, İ.
FK-space; AK-space; σK-space; σB-space;C_{1} summability method
In this paper we study the subspaces C_{1},C_{1}W,C_{1}F and
C_{1}B for a locally convex FK-space X containing Ф ,$ the space of finite sequences.
Department of Mathematics, University of Osijek
2002
text
info:eu-repo/semantics/article
info:eu-repo/semantics/publishedVersion
application/pdf
https://hrcak.srce.hr/778
https://hrcak.srce.hr/file/1510
Mathematical Communications
ISSN 1331-0623 (Print)
ISSN 1848-8013 (Online)
Volume 7
Issue 1
eng
info:eu-repo/semantics/openAccess
The full text of articles published in this journal can be used free of charge for personal and educational purposes while respecting authors' and publisher's copyrights. Annual subscription to printed copies is USD 50.00. Members of the Osijek Mathematical Society and the Mathematical Club of the Department of Mathematics receive this journal free of charge.
oai:hrcak.srce.hr:779
2008-06-03
journal:39
Some relations concerning k-chordal and k-tangential polygons
Radić, M.
geometrical inequalities; k-chordal polygon; k-tangential polygon
In papers [6] and [7] the k-chordal and the k-tangential polygons are defined and some of their properties are proved. In this paper we shall consider some of their other properties. Theorems 1-4 are proved.
Department of Mathematics, University of Osijek
2002
text
info:eu-repo/semantics/article
info:eu-repo/semantics/publishedVersion
application/pdf
https://hrcak.srce.hr/779
https://hrcak.srce.hr/file/1511
Mathematical Communications
ISSN 1331-0623 (Print)
ISSN 1848-8013 (Online)
Volume 7
Issue 1
eng
info:eu-repo/semantics/openAccess
The full text of articles published in this journal can be used free of charge for personal and educational purposes while respecting authors' and publisher's copyrights. Annual subscription to printed copies is USD 50.00. Members of the Osijek Mathematical Society and the Mathematical Club of the Department of Mathematics receive this journal free of charge.
oai:hrcak.srce.hr:780
2008-06-03
journal:39
The butterfly theorem for conics
Volenec, V.
Butterfly theorem
The butterfly theorem holds for any diameter of any conic.
Department of Mathematics, University of Osijek
2002
text
info:eu-repo/semantics/article
info:eu-repo/semantics/publishedVersion
application/pdf
https://hrcak.srce.hr/780
https://hrcak.srce.hr/file/1512
Mathematical Communications
ISSN 1331-0623 (Print)
ISSN 1848-8013 (Online)
Volume 7
Issue 1
eng
info:eu-repo/semantics/openAccess
The full text of articles published in this journal can be used free of charge for personal and educational purposes while respecting authors' and publisher's copyrights. Annual subscription to printed copies is USD 50.00. Members of the Osijek Mathematical Society and the Mathematical Club of the Department of Mathematics receive this journal free of charge.
oai:hrcak.srce.hr:781
2008-06-03
journal:39
An application of a genetic algorithm for throughput optimization in non-broadcast WDM optical networks with regular topologies
Podnar, H.
Skorin-Kapov, J.
wavelength division multiplexing; networks-graphs; network design; heuristics; genetic algorithms; regular topologies
We apply a genetic algorithm from Podnar and Skorin-Kapov
[5] to a virtual topology design of a Wide-Area WDM
Optical Network with regular topologies. Based on a given physical
topology a virtual topology consisting of optical lightpaths is constructed. The objective is to minimize the maximal throughput, which implies balancing link loads and accommodating on-growing
traffic requirements in a timely fashion.
The genetic algorithm is applied to benchmark instances of
regular topologies.
Department of Mathematics, University of Osijek
2002
text
info:eu-repo/semantics/article
info:eu-repo/semantics/publishedVersion
application/pdf
https://hrcak.srce.hr/781
https://hrcak.srce.hr/file/1513
Mathematical Communications
ISSN 1331-0623 (Print)
ISSN 1848-8013 (Online)
Volume 7
Issue 1
eng
info:eu-repo/semantics/openAccess
The full text of articles published in this journal can be used free of charge for personal and educational purposes while respecting authors' and publisher's copyrights. Annual subscription to printed copies is USD 50.00. Members of the Osijek Mathematical Society and the Mathematical Club of the Department of Mathematics receive this journal free of charge.
oai:hrcak.srce.hr:782
2008-06-03
journal:39
A correction for a result on convergence of Ishikawa iteration for strongly pseudocontractive maps
Şolutuz, Ş. M.
Ishikawa iteration; strongly pseudocontractive maps
We give a correction to the main result from [13].
Department of Mathematics, University of Osijek
2002
text
info:eu-repo/semantics/article
info:eu-repo/semantics/publishedVersion
application/pdf
https://hrcak.srce.hr/782
https://hrcak.srce.hr/file/1514
Mathematical Communications
ISSN 1331-0623 (Print)
ISSN 1848-8013 (Online)
Volume 7
Issue 1
eng
info:eu-repo/semantics/openAccess
The full text of articles published in this journal can be used free of charge for personal and educational purposes while respecting authors' and publisher's copyrights. Annual subscription to printed copies is USD 50.00. Members of the Osijek Mathematical Society and the Mathematical Club of the Department of Mathematics receive this journal free of charge.
oai:hrcak.srce.hr:783
2008-06-03
journal:39
On cyclic characterizations of regular pentagons and heptagons: Two approaches
Svrtan, D.
Šterc, D.
Urbiha, I.
pentagon; heptagon; cyclic equations; discrete Fourier transform; bi-unimodular sequences
In this paper we present two different proofs of an algebraic
characterization of regular pentagons and regular pentagrams in
terms of two cyclic (complex) algebraic equations on a
five--dimensional torus (Theorem1 and Theorem2). The problem arose in functional analysis (as communicated to one of the authors by A. Björner some twenty years ago). No published proof has appeared so far.
Apparently a proof was given by L. Lovász (unpublished and not
known to the authors). Here we give two different proofs, both
somewhat tricky. The first one relies upon discrete Fourier
transform and the second one is more direct. Also several
generalizations to heptagons are presented including an explicit
description of some new irregular heptagrams. Some additional
conjectures on general polygons are stated.
Department of Mathematics, University of Osijek
2002
text
info:eu-repo/semantics/article
info:eu-repo/semantics/publishedVersion
application/pdf
https://hrcak.srce.hr/783
https://hrcak.srce.hr/file/1516
Mathematical Communications
ISSN 1331-0623 (Print)
ISSN 1848-8013 (Online)
Volume 7
Issue 1
eng
info:eu-repo/semantics/openAccess
The full text of articles published in this journal can be used free of charge for personal and educational purposes while respecting authors' and publisher's copyrights. Annual subscription to printed copies is USD 50.00. Members of the Osijek Mathematical Society and the Mathematical Club of the Department of Mathematics receive this journal free of charge.
oai:hrcak.srce.hr:818
2008-06-03
journal:39
Stability and optimality in parametric convex programming models
Trujillo-Cortez, R.
Zlobec, S.
stable convex model; unstable convex model; optimal parameter; Lagrange multiplier function; LFS function
Equivalent conditions for structural stability are given for convex programming models in terms of three point-to-set mappings. These mappings are then used to characterize locally optimal parameters. For Lagrange models and, in particular, LFS models the
characterizations are given relative to general (possibly unstable) perturbations.
Department of Mathematics, University of Osijek
2001
text
info:eu-repo/semantics/article
info:eu-repo/semantics/publishedVersion
application/pdf
https://hrcak.srce.hr/818
https://hrcak.srce.hr/file/1583
Mathematical Communications
ISSN 1331-0623 (Print)
ISSN 1848-8013 (Online)
Volume 6
Issue 2
eng
info:eu-repo/semantics/openAccess
The full text of articles published in this journal can be used free of charge for personal and educational purposes while respecting authors' and publisher's copyrights. Annual subscription to printed copies is USD 50.00. Members of the Osijek Mathematical Society and the Mathematical Club of the Department of Mathematics receive this journal free of charge.
oai:hrcak.srce.hr:819
2008-06-03
journal:39
On weak convergence of functionals on smooth random functions
Rusakov, A.
Seleznjev, O.
random process; extremes; level crossings; weak convergence; Gaussian processes
The numbers of level crossings and extremes for random processes and fields play an important role in reliability theory and many engineering applications. In many cases for Gaussian processes the Poisson approximation for their asymptotic distributions is used.
This paper extends an approach proposed in Rusakov and Seleznjev (1988) for smooth random processes on a finite interval. It turns out that a number of functionals (including some integervalued ones) become continuous on the space of smooth functions and weak convergence results for the sequences of such continuous functionals
are applicable. Examples of such functionals for smooth random processes on infinite intervals and for random fields are studied.
Department of Mathematics, University of Osijek
2001
text
info:eu-repo/semantics/article
info:eu-repo/semantics/publishedVersion
application/pdf
https://hrcak.srce.hr/819
https://hrcak.srce.hr/file/1584
Mathematical Communications
ISSN 1331-0623 (Print)
ISSN 1848-8013 (Online)
Volume 6
Issue 2
eng
info:eu-repo/semantics/openAccess
The full text of articles published in this journal can be used free of charge for personal and educational purposes while respecting authors' and publisher's copyrights. Annual subscription to printed copies is USD 50.00. Members of the Osijek Mathematical Society and the Mathematical Club of the Department of Mathematics receive this journal free of charge.
oai:hrcak.srce.hr:820
2008-06-03
journal:39
Random walk tests for pseudo-random number generators
Markovski, S.
Gligoroski, D.
Bakeva, V.
random sequence, random walk, PRNG (pseudo-random number generator), normal distribution;Χ^2 -test
It is well known that there are no perfectly good generators of random number sequences, implying the need of testing the randomness of the sequences produced by such generators. There are many tests for measuring the uniformity of random sequences, and here we propose a few new ones, designed by random walks. The experiments we have made show that our tests discover some discrepancies of random sequences passing many other tests.
Department of Mathematics, University of Osijek
2001
text
info:eu-repo/semantics/article
info:eu-repo/semantics/publishedVersion
application/pdf
https://hrcak.srce.hr/820
https://hrcak.srce.hr/file/1585
Mathematical Communications
ISSN 1331-0623 (Print)
ISSN 1848-8013 (Online)
Volume 6
Issue 2
eng
info:eu-repo/semantics/openAccess
The full text of articles published in this journal can be used free of charge for personal and educational purposes while respecting authors' and publisher's copyrights. Annual subscription to printed copies is USD 50.00. Members of the Osijek Mathematical Society and the Mathematical Club of the Department of Mathematics receive this journal free of charge.
oai:hrcak.srce.hr:821
2008-06-03
journal:39
One-step behaviour of a method for finding a maximal solution of a system of linear inequalities
Späth, H.
Watson, G. A.
sequential linear programming; one-step behaviour; maximal solution of linear inequalities
It has been observed empirically that a simple linearization method applied to the problem of finding maximal solutions to systems of linear inequalities frequently terminates in one step.
This is normally a Kuhn-Tucker point, and depending on the starting point, can be a global solution.
An explanation of this phenomenon is given, and this is illustrated by examples.
Department of Mathematics, University of Osijek
2001
text
info:eu-repo/semantics/article
info:eu-repo/semantics/publishedVersion
application/pdf
https://hrcak.srce.hr/821
https://hrcak.srce.hr/file/1586
Mathematical Communications
ISSN 1331-0623 (Print)
ISSN 1848-8013 (Online)
Volume 6
Issue 2
eng
info:eu-repo/semantics/openAccess
The full text of articles published in this journal can be used free of charge for personal and educational purposes while respecting authors' and publisher's copyrights. Annual subscription to printed copies is USD 50.00. Members of the Osijek Mathematical Society and the Mathematical Club of the Department of Mathematics receive this journal free of charge.
oai:hrcak.srce.hr:822
2008-06-03
journal:39
On NP - polyagroups
Ušan, J.
Galić, R.
{1;n}-neutral operation; n-group; n-semigroup; n-quasigroup; Ps-associative n-groupoid; P-polyagroup; NP-polyagroup
In the present paper: 1) an NP--polyagroup is defined as a
generalization of an $n-$group for $ngeq 3;$ and 2)
NP--polyagroups of the type $(s,n-1)$ is described as algebras
of the type $<n,n-1,n-2>$ [$,=<kcdot s+1,kcdot s,kcdot
s-1>; k>1,sgeq 1$ ].
Department of Mathematics, University of Osijek
2001
text
info:eu-repo/semantics/article
info:eu-repo/semantics/publishedVersion
application/pdf
https://hrcak.srce.hr/822
https://hrcak.srce.hr/file/1587
Mathematical Communications
ISSN 1331-0623 (Print)
ISSN 1848-8013 (Online)
Volume 6
Issue 2
eng
info:eu-repo/semantics/openAccess
The full text of articles published in this journal can be used free of charge for personal and educational purposes while respecting authors' and publisher's copyrights. Annual subscription to printed copies is USD 50.00. Members of the Osijek Mathematical Society and the Mathematical Club of the Department of Mathematics receive this journal free of charge.
oai:hrcak.srce.hr:823
2008-06-03
journal:39
A generalization of the butterfly theorem from circles to conics
Čerin, Z.
Butterfly theorem; conic
This paper presents a generalization of the Butterfly Theorem that is true for all conic curves.
Department of Mathematics, University of Osijek
2001
text
info:eu-repo/semantics/article
info:eu-repo/semantics/publishedVersion
application/pdf
https://hrcak.srce.hr/823
https://hrcak.srce.hr/file/1588
Mathematical Communications
ISSN 1331-0623 (Print)
ISSN 1848-8013 (Online)
Volume 6
Issue 2
eng
info:eu-repo/semantics/openAccess
The full text of articles published in this journal can be used free of charge for personal and educational purposes while respecting authors' and publisher's copyrights. Annual subscription to printed copies is USD 50.00. Members of the Osijek Mathematical Society and the Mathematical Club of the Department of Mathematics receive this journal free of charge.
oai:hrcak.srce.hr:824
2008-06-03
journal:39
I-limit superior and limit inferior
Demirci, K.
statistical limit superior and inferior; statistical core of a sequence; I-convergent sequence
In this paper we extend concepts of statistical limit superior and
inferior (as introduced by Fridy and Orhan) to $mathcal{I-}$limit superior and inferior and give some $mathcal{I-}$analogue of properties of statistical limit superior and inferior for a sequence of real numbers. Also we extend the concept of the statistical core to $mathcal{I-}$core for a complex number sequence and get necessary conditions for a summability
matrix $A$ to yield $mathcal{I-}coreleft{ Axright} $ $subseteq
mathcal{I-}coreleft{ xright} $ whenever $x$ is a bounded complex number
sequence.
Department of Mathematics, University of Osijek
2001
text
info:eu-repo/semantics/article
info:eu-repo/semantics/publishedVersion
application/pdf
https://hrcak.srce.hr/824
https://hrcak.srce.hr/file/1589
Mathematical Communications
ISSN 1331-0623 (Print)
ISSN 1848-8013 (Online)
Volume 6
Issue 2
eng
info:eu-repo/semantics/openAccess
The full text of articles published in this journal can be used free of charge for personal and educational purposes while respecting authors' and publisher's copyrights. Annual subscription to printed copies is USD 50.00. Members of the Osijek Mathematical Society and the Mathematical Club of the Department of Mathematics receive this journal free of charge.
oai:hrcak.srce.hr:825
2008-06-03
journal:39
Least squares fitting with rotated paraboloids
Späth, H.
least squares; paraboloid; rotated paraboloid; descent method
In [1] the problem of estimating the parameters of a rotated parabola fitted to measured points in the plane was examined. The
corresponding method, also used in [2,3], is extended
here to the case of a rotated paraboloid. Fitting by such a surface occurs in computational metrology e.g. when some parabolic reflector will be checked to be a good one.
Department of Mathematics, University of Osijek
2001
text
info:eu-repo/semantics/article
info:eu-repo/semantics/publishedVersion
application/pdf
https://hrcak.srce.hr/825
https://hrcak.srce.hr/file/1590
Mathematical Communications
ISSN 1331-0623 (Print)
ISSN 1848-8013 (Online)
Volume 6
Issue 2
eng
info:eu-repo/semantics/openAccess
The full text of articles published in this journal can be used free of charge for personal and educational purposes while respecting authors' and publisher's copyrights. Annual subscription to printed copies is USD 50.00. Members of the Osijek Mathematical Society and the Mathematical Club of the Department of Mathematics receive this journal free of charge.
oai:hrcak.srce.hr:826
2008-06-03
journal:39
Some properties of a function studied by De Rham, Carlitz and Dijkstra and its relation to the (Eisenstein-)Stern's diatomic sequence
Urbiha, I.
recurrences; reduced fractions; continuants; (hyper) binary representation; Stern's diatomic sequence; 2-adic order; Stern-Brocot tree; Jacobsthal's numbers
We present a novel approach to a remarkable function
D: N_0→N_0 defined by D(0)=0, D(1)=1, D(2n)=D(n), D(2n+1)=D(n)+D(n+1), studied independently by well known researchers in different areas of mathematics and computer science. Besides some
known properties we add some new ones (including a relation to the
(Eisenstein-)Stern's diatomic sequence). Some historical remarks are added at the end of this paper.
Department of Mathematics, University of Osijek
2001
text
info:eu-repo/semantics/article
info:eu-repo/semantics/publishedVersion
application/pdf
https://hrcak.srce.hr/826
https://hrcak.srce.hr/file/1591
Mathematical Communications
ISSN 1331-0623 (Print)
ISSN 1848-8013 (Online)
Volume 6
Issue 2
eng
info:eu-repo/semantics/openAccess
The full text of articles published in this journal can be used free of charge for personal and educational purposes while respecting authors' and publisher's copyrights. Annual subscription to printed copies is USD 50.00. Members of the Osijek Mathematical Society and the Mathematical Club of the Department of Mathematics receive this journal free of charge.
oai:hrcak.srce.hr:827
2008-06-03
journal:39
Hyperspaces which are products or cones
Lončar, I.
hyperspace; inverse system
Let C(X) be the hyperspace of all subcontinua of a metric continuum X.
Alejandro Illanes has proved that C(X) is a finite-dimensional Cartesian product if and only if X is an arc or a circle. In this paper we shall prove, using the inverse systems and limits, that if X is a non-metric rim-metrizable continuum and C(X) is a finite-dimensional Cartesian product, then X is a generalized arc or a generalized circle.
It is also proved that if X is a non-metric continuum such that
dim(X)<∞ and such that X has the cone = hyperspace property, then X is ageneralized arc, a generalized circle, or an indecomposable continuum such that each nondegenerate proper subcontinuum of X is a generalized arc.
Department of Mathematics, University of Osijek
2001
text
info:eu-repo/semantics/article
info:eu-repo/semantics/publishedVersion
application/pdf
https://hrcak.srce.hr/827
https://hrcak.srce.hr/file/1592
Mathematical Communications
ISSN 1331-0623 (Print)
ISSN 1848-8013 (Online)
Volume 6
Issue 2
eng
info:eu-repo/semantics/openAccess
The full text of articles published in this journal can be used free of charge for personal and educational purposes while respecting authors' and publisher's copyrights. Annual subscription to printed copies is USD 50.00. Members of the Osijek Mathematical Society and the Mathematical Club of the Department of Mathematics receive this journal free of charge.
oai:hrcak.srce.hr:828
2008-06-03
journal:39
On some primary and secondary structures in combinatorics
Veljan, D.
Catalan numbers; Narayana numbers; Motzkin numbers; secondary structure; log-convexity
A possible upgrade of a curriculum in undergraduate
course in combinatorics is presented by giving more bijective
proofs in the standard (or primary) combinatorics and by adding
some topics on more refined (or secondary) combinatorics,
including Dyck and Motzkin paths, Catalan, Narayana and Motzkin
numbers and secondary structures coming from biology. Some
log-convexity properties and asymptotics of these numbers are
also presented.
Department of Mathematics, University of Osijek
2001
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https://hrcak.srce.hr/828
https://hrcak.srce.hr/file/1593
Mathematical Communications
ISSN 1331-0623 (Print)
ISSN 1848-8013 (Online)
Volume 6
Issue 2
eng
info:eu-repo/semantics/openAccess
The full text of articles published in this journal can be used free of charge for personal and educational purposes while respecting authors' and publisher's copyrights. Annual subscription to printed copies is USD 50.00. Members of the Osijek Mathematical Society and the Mathematical Club of the Department of Mathematics receive this journal free of charge.
oai:hrcak.srce.hr:829
2008-06-03
journal:39
Computational aspects of probit model
Demidenko, E.
probit model; cut-off-error; maximum likelihood; existence; binary data; binary model
Sometimes the maximum likelihood estimation procedure for the probit model fails. There may be two reasons: the maximum likelihood estimate (MLE) just does not exist or computer overflow error occurs during the computation of the cumulative distribution function (cdf). For example, the approximation explosive effect due to an inaccurate computation of the cdf for a large value of the argument occurs in a popular statistical package S-plus. The goal of
the paper is to provide remedies for these two abnormalities. First, despite the availability of a criterion for the MLE existence, expressed in terms of a separation plane in the covariate space, there are no constructive criteria to verify whether such a separation exists. We develop constructive criteria for the MLE existence that are valid also for other link functions. Second, to avoid the overflow problem we suggest approximate formulae for the log-likelihood function and its derivatives in the case of possiblelarge value of the argument. Standard algorithms of the log-likelihood maximization like Newton-Raphson or Fisher Scoring are very sensitive to large values of the linear predictor, particularly outliers. Five algorithms are compared by the time to converge and reliability via statistical simulations. The corrected algorithms, based on the approximate formulae are
more reliable and almost as fast as the standard ones
Department of Mathematics, University of Osijek
2001
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https://hrcak.srce.hr/829
https://hrcak.srce.hr/file/1594
Mathematical Communications
ISSN 1331-0623 (Print)
ISSN 1848-8013 (Online)
Volume 6
Issue 2
eng
info:eu-repo/semantics/openAccess
The full text of articles published in this journal can be used free of charge for personal and educational purposes while respecting authors' and publisher's copyrights. Annual subscription to printed copies is USD 50.00. Members of the Osijek Mathematical Society and the Mathematical Club of the Department of Mathematics receive this journal free of charge.
oai:hrcak.srce.hr:831
2008-06-03
journal:39
A note on a Whitney map for continua
Lončar, I.
continuum; hyperspace; inverse system
Let X be a non-metric continuum, and C(X) the hyperspace of subcontinua of X. It is known that there is no Whitney map on the hyperspace 2^X for non-metrizable Hausdorff compact spaces X.
On the other hand, there exist non-metrizable continua which admit
and the ones which do not admit a Whitney map for C(X). In this paper we investigate the properties of non-metrizable continua which
admit a Whitney map and the ones which do not admit a Whitney map for C(X). It is shown that there is no Whitney map on the hyperspace
C(X) if X is a non-metrizable locally connected or rim-metrizable
continuum.
Department of Mathematics, University of Osijek
2001
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https://hrcak.srce.hr/831
https://hrcak.srce.hr/file/1597
Mathematical Communications
ISSN 1331-0623 (Print)
ISSN 1848-8013 (Online)
Volume 6
Issue 1
eng
info:eu-repo/semantics/openAccess
The full text of articles published in this journal can be used free of charge for personal and educational purposes while respecting authors' and publisher's copyrights. Annual subscription to printed copies is USD 50.00. Members of the Osijek Mathematical Society and the Mathematical Club of the Department of Mathematics receive this journal free of charge.
oai:hrcak.srce.hr:832
2008-06-03
journal:39
The dynamics of some cubic vector fields with a center
Županović, V.
cubic vector fields
We study planar cubic vector fields
[V_H=yP_2frac{partial}{partial x}-x Q_2frac{partial}{partial y}] with a center, having Darboux first integral $H=P_1^2Q_3$. We give the bifurcation diagram of the phase portraits of the vector fields, in 2-dimensional parameter space.
Department of Mathematics, University of Osijek
2001
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https://hrcak.srce.hr/832
https://hrcak.srce.hr/file/1598
Mathematical Communications
ISSN 1331-0623 (Print)
ISSN 1848-8013 (Online)
Volume 6
Issue 1
eng
info:eu-repo/semantics/openAccess
The full text of articles published in this journal can be used free of charge for personal and educational purposes while respecting authors' and publisher's copyrights. Annual subscription to printed copies is USD 50.00. Members of the Osijek Mathematical Society and the Mathematical Club of the Department of Mathematics receive this journal free of charge.
oai:hrcak.srce.hr:833
2008-06-03
journal:39
On a sequential linear programming approach to finding the smallest circumscribed, largest inscribed, and minimum zone circle or sphere
Späth, H.
Watson, G. A.
sequential linear programming; smallest circumscribed; largest inscribed; minimum zone
Sequential linear programming methods have been successfully
used to solve some sphere and circle problems. Indeed, empirical evidence shows that these frequently find the required solutions in one step. An analysis is presented here which attempts to give an explanation of this phenomemon.
Department of Mathematics, University of Osijek
2001
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https://hrcak.srce.hr/833
https://hrcak.srce.hr/file/1599
Mathematical Communications
ISSN 1331-0623 (Print)
ISSN 1848-8013 (Online)
Volume 6
Issue 1
eng
info:eu-repo/semantics/openAccess
The full text of articles published in this journal can be used free of charge for personal and educational purposes while respecting authors' and publisher's copyrights. Annual subscription to printed copies is USD 50.00. Members of the Osijek Mathematical Society and the Mathematical Club of the Department of Mathematics receive this journal free of charge.
oai:hrcak.srce.hr:834
2008-06-03
journal:39
Minisum location in space with restriction to curves and surfaces
Späth, H.
minisum location problem; side conditions; Weiszfeld iteration
The minisum location problem is well-known and has extensively been studied in the case of the unknown location being somewhere in the space. Also the accompanying Weiszfeld iteration method [1,2,3] is well understood nowadays, even for noneuclidean distances. We introduce as a side condition for the unknown optimal location that it lies on some given curve or surface in space. For the straight line, the plane, the sphere, and the circle the corresponding Weiszfeld-like iteration methods are developed and numerical examples are given.
Department of Mathematics, University of Osijek
2001
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https://hrcak.srce.hr/834
https://hrcak.srce.hr/file/1600
Mathematical Communications
ISSN 1331-0623 (Print)
ISSN 1848-8013 (Online)
Volume 6
Issue 1
eng
info:eu-repo/semantics/openAccess
The full text of articles published in this journal can be used free of charge for personal and educational purposes while respecting authors' and publisher's copyrights. Annual subscription to printed copies is USD 50.00. Members of the Osijek Mathematical Society and the Mathematical Club of the Department of Mathematics receive this journal free of charge.
oai:hrcak.srce.hr:835
2008-06-03
journal:39
Least squares estimation of regression coefficients of singular random fields observed on a sphere
Anh, V.V.
Leonenko, N.N.
Sharapov, M.M.
long-range dependence; random fields with singular spectrum; regression on a sphere
We present some results on the rate of convergence to the normal law of the least square estimates of the regression coefficient of random fields with long range dependence observed on a sphere.
Department of Mathematics, University of Osijek
2001
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https://hrcak.srce.hr/835
https://hrcak.srce.hr/file/1601
Mathematical Communications
ISSN 1331-0623 (Print)
ISSN 1848-8013 (Online)
Volume 6
Issue 1
eng
info:eu-repo/semantics/openAccess
The full text of articles published in this journal can be used free of charge for personal and educational purposes while respecting authors' and publisher's copyrights. Annual subscription to printed copies is USD 50.00. Members of the Osijek Mathematical Society and the Mathematical Club of the Department of Mathematics receive this journal free of charge.
oai:hrcak.srce.hr:836
2008-06-03
journal:39
On algebraic equations concerning semi-tangential polygons
Radić, M.
algebraic equation; semi-tangential polygon
Some properties of equations (5) and (6) are proved (Theorem 1-2) and it was established that the positive roots of these equations are radii of a sequence of tangential semi-polygons which have the same lengths of tangents.
Department of Mathematics, University of Osijek
2001
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https://hrcak.srce.hr/836
https://hrcak.srce.hr/file/1602
Mathematical Communications
ISSN 1331-0623 (Print)
ISSN 1848-8013 (Online)
Volume 6
Issue 1
eng
info:eu-repo/semantics/openAccess
The full text of articles published in this journal can be used free of charge for personal and educational purposes while respecting authors' and publisher's copyrights. Annual subscription to printed copies is USD 50.00. Members of the Osijek Mathematical Society and the Mathematical Club of the Department of Mathematics receive this journal free of charge.
oai:hrcak.srce.hr:837
2008-06-03
journal:39
Unique symmetric (66,26,10) design admitting an automorphism of order 55
Crnković, D.
Rukavina, S.
symmetric design; automorphism group; orbit structure
We have proved that the first known symmetric (66,26,10) design, constructed by Tran van Trung, is up to isomorphism the only symmetric (66,26,10) design admitting an automorphism
of order 55. A full automorphism group of that design is isomorphic to
Frob_{55}times D_{10}.
Department of Mathematics, University of Osijek
2001
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https://hrcak.srce.hr/837
https://hrcak.srce.hr/file/1603
Mathematical Communications
ISSN 1331-0623 (Print)
ISSN 1848-8013 (Online)
Volume 6
Issue 1
eng
info:eu-repo/semantics/openAccess
The full text of articles published in this journal can be used free of charge for personal and educational purposes while respecting authors' and publisher's copyrights. Annual subscription to printed copies is USD 50.00. Members of the Osijek Mathematical Society and the Mathematical Club of the Department of Mathematics receive this journal free of charge.
oai:hrcak.srce.hr:839
2008-06-03
journal:39
Least squares fitting of spheres and ellipsoids using not orthogonal distances
Späth, H.
least squares; not orthogonal distances; ellipsoid; sphere
Berman [1] examined the problem of estimating the parameters of a
circle when angular differences between successively measured data points were also measured. Applications were reported. Späth [4] generalized that problem by considering an ellipse. Now we will consider measured data points (x_k,y_k,z_k) in space and also associated measured angles
(u_k,v_k) k=1, ..., n>8, for the canonical parametric representation
of a sphere or an ellipsoid. The center and the radius or the three half
axes, respectively, and two other parameters will be fitted such that some suitable sum of squared not orthogonal distances between the two measurements is minimized. Numerical examples are given. Generalizations are discussed. Another numerical method was proposed by Watson [5].
Department of Mathematics, University of Osijek
2001
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https://hrcak.srce.hr/839
https://hrcak.srce.hr/file/1606
Mathematical Communications
ISSN 1331-0623 (Print)
ISSN 1848-8013 (Online)
Volume 6
Issue 1
eng
info:eu-repo/semantics/openAccess
The full text of articles published in this journal can be used free of charge for personal and educational purposes while respecting authors' and publisher's copyrights. Annual subscription to printed copies is USD 50.00. Members of the Osijek Mathematical Society and the Mathematical Club of the Department of Mathematics receive this journal free of charge.
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