2020-10-26T01:18:39Z
https://hrcak.srce.hr/oai/
oai:hrcak.srce.hr:373
2008-06-03
journal:27
Identities with derivations on rings and Banach algebras
Vukman, Joso
Prime ring; semiprime ring; Banach algebra; derivation; commuting mapping; centralizing mapping; skew-commuting mapping; skew-centralizing mapping
In this paper we prove the following result. Let m 1, n 1 be integers and let R be a 2mn(m+n-1)!-torsion free semiprime ring. Suppose there exist derivations D, G : R R such that D(xm)xn + xnG(xm) = 0 holds for all x R. In this case both derivations D and G map R into its center and D = -G. We apply this purely algebraic result to obtain a range inclusion result of continuous derivations on Banach algebras.
Croatian Mathematical Society and Department of Mathematics, University of Zagreb
2005
text
info:eu-repo/semantics/article
info:eu-repo/semantics/publishedVersion
application/pdf
https://hrcak.srce.hr/373
https://hrcak.srce.hr/file/224
Glasnik matematički
ISSN 0017-095X (Print)
ISSN 1846-7989 (Online)
Volume 40
Issue 2
eng
info:eu-repo/semantics/openAccess
oai:hrcak.srce.hr:374
2008-06-03
journal:27
Alternate proofs of some basic theorems of finite group theory
Berkovich, Yakov
Sylow p-subgroup; solvable group; Hall subgroup; Carter subgroup
In this note alternate proofs of some basic results of finite group theory are presented.
Croatian Mathematical Society and Department of Mathematics, University of Zagreb
2005
text
info:eu-repo/semantics/article
info:eu-repo/semantics/publishedVersion
application/pdf
https://hrcak.srce.hr/374
https://hrcak.srce.hr/file/913
Glasnik matematički
ISSN 0017-095X (Print)
ISSN 1846-7989 (Online)
Volume 40
Issue 2
eng
info:eu-repo/semantics/openAccess
oai:hrcak.srce.hr:375
2008-06-03
journal:27
Finite p-groups with a uniqueness condition for non-normal subgroups
Janko, Zvonimir
Finite p-groups; minimal nonabelian p-groups; 2-groups of maximal class; Hamiltonian groups
We determine up to isomorphism all finite p-groups G which possess non-normal subgroups and each non-normal subgroup is contained in exactly one maximal subgroup of G. For p = 2 this problem was essentially more difficult and we obtain in that case two new infinite families of finite 2-groups.
Croatian Mathematical Society and Department of Mathematics, University of Zagreb
2005
text
info:eu-repo/semantics/article
info:eu-repo/semantics/publishedVersion
application/pdf
https://hrcak.srce.hr/375
https://hrcak.srce.hr/file/914
Glasnik matematički
ISSN 0017-095X (Print)
ISSN 1846-7989 (Online)
Volume 40
Issue 2
eng
info:eu-repo/semantics/openAccess
oai:hrcak.srce.hr:376
2008-06-03
journal:27
An equation on operator algebras and semisimple H*-algebras
Vukman, Joso
Prime ring; semiprime ring; Banach space; standard operator algebra; H*-algebra; derivation; Jordan derivation; left (right) centralizer; left (right) Jordan centralizer
In this paper we prove the following result: Let X be a Banach space over the real or complex field F and let L(X) be the algebra of all bounded linear operators on X. Suppose there exists an additive mapping T : A(X) L(X), where A(X) L(X) is a standard operator algebra. Suppose that
T(A3) = AT(A)A
holds for all A A(X). In this case T is of the form T(A) = A for any A A(X) and some F. This result is applied to semisimple H*-algebras.
Croatian Mathematical Society and Department of Mathematics, University of Zagreb
2005
text
info:eu-repo/semantics/article
info:eu-repo/semantics/publishedVersion
application/pdf
https://hrcak.srce.hr/376
https://hrcak.srce.hr/file/915
Glasnik matematički
ISSN 0017-095X (Print)
ISSN 1846-7989 (Online)
Volume 40
Issue 2
eng
info:eu-repo/semantics/openAccess
oai:hrcak.srce.hr:377
2008-06-03
journal:27
Convexifiable functions in integral calculus
Zlobec, Sanjo
Convex function; convexifiable function; integral mean value; Jensen's inequality; analytic function
A function is said to be convexifiable if it becomes convex after adding to it a strictly convex quadratic term. In this paper we extend some of the basic integral properties of convex functions to Lipschitz continuously differentiable functions on real line. In particular, we give estimates of the mean value, a "nonstandard" form of Jensen's inequality, and an explicit representation of analytic functions. It is also outlined how one can use convexification to study ordinary differential equations.
Croatian Mathematical Society and Department of Mathematics, University of Zagreb
2005
text
info:eu-repo/semantics/article
info:eu-repo/semantics/publishedVersion
application/pdf
https://hrcak.srce.hr/377
https://hrcak.srce.hr/file/916
Glasnik matematički
ISSN 0017-095X (Print)
ISSN 1846-7989 (Online)
Volume 40
Issue 2
eng
info:eu-repo/semantics/openAccess
oai:hrcak.srce.hr:378
2008-06-03
journal:27
Unstable neutral differential equations involving the maximum function
Zhang, Guang
Migda, Malgorzata
Differential equation; maximum function; nonoscillation; oscillation; asymptotic property
A nonlinear differential equation involving the maximum function is studied. The existence and asymptotic behavior of nonoscillatory solutions are considered. The difference between the positive and negative solutions is illustrated by some examples. Oscillation of solutions is also studied.
Croatian Mathematical Society and Department of Mathematics, University of Zagreb
2005
text
info:eu-repo/semantics/article
info:eu-repo/semantics/publishedVersion
application/pdf
https://hrcak.srce.hr/378
https://hrcak.srce.hr/file/917
Glasnik matematički
ISSN 0017-095X (Print)
ISSN 1846-7989 (Online)
Volume 40
Issue 2
eng
info:eu-repo/semantics/openAccess
oai:hrcak.srce.hr:379
2008-06-03
journal:27
S-diagonalizable operators in quantum mechanics
Carfi, David
Linear operator; tempered distribution; basis; linear superposition; eigenvalue; diagonalizability
In this paper we study a certain class of endomorphisms on the space of tempered distributions. More precisely, the core of the paper deals with endomorphisms, defined on the whole space of tempered distributions, for which there exists an S-basis of the space formed by their eigenvectors. We call these operators S-diagonalizable operators. One of the goals of the paper is the realization that this class of endomorphisms represents in the infinite-dimensional case what in finite-dimension is represented by the diagonalizable matrices.
We concentrate our examination on two aspects: the study of the spectrum of these operators and the foundation of a functional calculus for them. Concerning the first aspect, we do not assume nothing about the spectrum of these operators. The circumstance that the eigenvalue-spectrum of these operators will be continuous (more precisely it will be a connected subset of the complex plane, as it is proved in the present note) is a consequence of our definition. Moreover, the spectral measures will be not used in the construction of the functional calculus. In such a way, the definition of the function of an operator, presented in the paper, differs deeply from the usual one, in which the spectral measures of the operators play a fundamental role (as in the spectral decomposition of an operator). Note that, even in the case in which the eigenvalues-spectrum is a subset of the real line, we show that it is not necessarily coinciding with the whole real line.
Croatian Mathematical Society and Department of Mathematics, University of Zagreb
2005
text
info:eu-repo/semantics/article
info:eu-repo/semantics/publishedVersion
application/pdf
https://hrcak.srce.hr/379
https://hrcak.srce.hr/file/918
Glasnik matematički
ISSN 0017-095X (Print)
ISSN 1846-7989 (Online)
Volume 40
Issue 2
eng
info:eu-repo/semantics/openAccess
oai:hrcak.srce.hr:380
2008-06-03
journal:27
Direct limit of matrix ordered spaces
Ramani, J. V.
Karn, Anil K.
Yadav, Sunil
f-bimodule; direct limit
In this paper we initiate the study of ordered f-bimodules as the inductive limit of matrix ordered spaces.
Croatian Mathematical Society and Department of Mathematics, University of Zagreb
2005
text
info:eu-repo/semantics/article
info:eu-repo/semantics/publishedVersion
application/pdf
https://hrcak.srce.hr/380
https://hrcak.srce.hr/file/919
Glasnik matematički
ISSN 0017-095X (Print)
ISSN 1846-7989 (Online)
Volume 40
Issue 2
eng
info:eu-repo/semantics/openAccess
oai:hrcak.srce.hr:381
2008-06-03
journal:27
Three-dimensional hyperbolic geometry with planes and plane parallelism as only primitive notions
Pambuccian, Victor
Hyperbolic space; Euclidean Möbius plane; axiom system
We show that Euclidean Möbius planes can be axiomatized in terms of circles and circle-tangency, and that 3-dimensional hyperbolic geometry can be axiomatized in terms of planes and plane-parallelism.
Croatian Mathematical Society and Department of Mathematics, University of Zagreb
2005
text
info:eu-repo/semantics/article
info:eu-repo/semantics/publishedVersion
application/pdf
https://hrcak.srce.hr/381
https://hrcak.srce.hr/file/920
Glasnik matematički
ISSN 0017-095X (Print)
ISSN 1846-7989 (Online)
Volume 40
Issue 2
eng
info:eu-repo/semantics/openAccess
oai:hrcak.srce.hr:382
2008-06-03
journal:27
On rarely g-continuous functions
Caldas, Miguel
Jafari, Saeid
Rare set; g-open; rarely continuous; rarely almost compact
Popa introduced the notion of rare continuity. In this paper, we introduce a new class of functions called rarely g-continuous functions and investigate some of its fundamental properties. This type of continuity is a generalization of both rare continuity and weak continuity.
Croatian Mathematical Society and Department of Mathematics, University of Zagreb
2005
text
info:eu-repo/semantics/article
info:eu-repo/semantics/publishedVersion
application/pdf
https://hrcak.srce.hr/382
https://hrcak.srce.hr/file/228
Glasnik matematički
ISSN 0017-095X (Print)
ISSN 1846-7989 (Online)
Volume 40
Issue 2
eng
info:eu-repo/semantics/openAccess
oai:hrcak.srce.hr:383
2008-06-03
journal:27
Equivariant fibrant spaces
Bykov, Alexander
Texis, Marcelino
Fibration; fibrant space; G-ANR
In this paper the concept of a G-fibrant space is introduced. It is shown that any compact metrizable group G is a G-fibrant.
Croatian Mathematical Society and Department of Mathematics, University of Zagreb
2005
text
info:eu-repo/semantics/article
info:eu-repo/semantics/publishedVersion
application/pdf
https://hrcak.srce.hr/383
https://hrcak.srce.hr/file/922
Glasnik matematički
ISSN 0017-095X (Print)
ISSN 1846-7989 (Online)
Volume 40
Issue 2
eng
info:eu-repo/semantics/openAccess
oai:hrcak.srce.hr:384
2008-06-03
journal:27
D-continuum X admits a Whitney map for C(X) if and only if it is metrizable
Lončar, Ivan
D-continuum; Whitney map
The main purpose of this paper is to prove:
a) a D-continuum X admits a Whitney map for C(X) if and only if it is metrizable,
b) a continuum X admits a Whitney map for C2(X) if and only if it is metrizable.
Croatian Mathematical Society and Department of Mathematics, University of Zagreb
2005
text
info:eu-repo/semantics/article
info:eu-repo/semantics/publishedVersion
application/pdf
https://hrcak.srce.hr/384
https://hrcak.srce.hr/file/923
Glasnik matematički
ISSN 0017-095X (Print)
ISSN 1846-7989 (Online)
Volume 40
Issue 2
eng
info:eu-repo/semantics/openAccess
oai:hrcak.srce.hr:385
2008-06-03
journal:27
A local to global selection theorem for simplex-valued functions
Ivanšić, Ivan
Rubin, Leonard R.
Contiguous functions; continuous function; discrete collection; infinite simplex; K-modification; locally finite-dimensional complex; paracompact; polyhedron; principal simplex; selection; simplex; simplicial complex
Suppose we are given a function : X K where X is a paracompact space and K is a simplicial complex, and an open cover {U | } of X, so that for each , f : U |K| is a map that is a selection of on its domain. We shall prove that there is a map f : X |K| which is a selection of . We shall also show that under certain conditions on such a set of maps or on the complex K, there exists a : X K with the property that each f is a selection of on its domain and that there is a selection f : X |K| of . The term selection, as used herein, will always refer to a map f, i.e., continuous function, having the property that f(x) (x) for each x in the domain.
Croatian Mathematical Society and Department of Mathematics, University of Zagreb
2005
text
info:eu-repo/semantics/article
info:eu-repo/semantics/publishedVersion
application/pdf
https://hrcak.srce.hr/385
https://hrcak.srce.hr/file/924
Glasnik matematički
ISSN 0017-095X (Print)
ISSN 1846-7989 (Online)
Volume 40
Issue 2
eng
info:eu-repo/semantics/openAccess
oai:hrcak.srce.hr:386
2008-06-03
journal:27
A subshape spectrum for compacta
Uglešić, Nikica
Červar, Branko
Compactum; ANR; inverse sequence; limit; shape type; quasi-equivalence; S-equivalence
A sequence of categories and functors between them are constructed. They form a subshape spectrum for compacta in the following sense: Each of these categories classifies compact ANR's just as the homotopy category does; the classification of compacta by the "finest" of these categories coincides with the shape type classification; moreover, the finest category contains a subcategory which is isomorphic to the shape category; there exists a functor of the shape category to each of these categories, as well as of a "finer" category to a "coarser" one; the functors commute according to the indices.
Further, a few applications of the "subshape spectrum theory" are demonstrated. It is shown that the S*-equivalence (a uniformization of the Mardesic S-equivalence) and the q*-equivalence (a uniformization of the Borsuk quasi-equivalence) admit the category characterizations within the subshape spectrum, and that the q*-equivalence implies (but is not equivalent to) the S*-equivalence.
Croatian Mathematical Society and Department of Mathematics, University of Zagreb
2005
text
info:eu-repo/semantics/article
info:eu-repo/semantics/publishedVersion
application/pdf
https://hrcak.srce.hr/386
https://hrcak.srce.hr/file/925
Glasnik matematički
ISSN 0017-095X (Print)
ISSN 1846-7989 (Online)
Volume 40
Issue 2
eng
info:eu-repo/semantics/openAccess
oai:hrcak.srce.hr:392
2008-06-03
journal:27
Biplanes (56,11,2) with a fixed-point-free involutory automorphism
Essert, Mario
Marangunić, Ljubo
Biplane; design; automorphism group; orbit; orbit structure
The aim of this article is to prove that exactly four biplanes with parameters (56,11,2) admit a fixed-point-free action of an involutory automorphism. These are: Hall's biplane B20, Salwach and Mezzaroba's biplane B22, Denniston's biplane B24 and Denniston's biplane B26.
Croatian Mathematical Society and Department of Mathematics, University of Zagreb
2005
text
info:eu-repo/semantics/article
info:eu-repo/semantics/publishedVersion
application/pdf
https://hrcak.srce.hr/392
https://hrcak.srce.hr/file/936
Glasnik matematički
ISSN 0017-095X (Print)
ISSN 1846-7989 (Online)
Volume 40
Issue 1
eng
info:eu-repo/semantics/openAccess
oai:hrcak.srce.hr:393
2008-06-03
journal:27
On shifted products which are powers
Luca, Florian
Shifted products; perfect powers
In this note, we improve upon results of Bugeaud, Gyarmati, Sarkozy and Stewart concerning the size of a subset A of {1,...,N} such that the product of any two distinct elements of A plus 1 is a perfect power. We also show that the cardinality of such a set is uniformly bounded assuming the ABC-conjecture, thus improving upon a result of Dietmann, Elsholtz, Gyarmati and Simonovits.
Croatian Mathematical Society and Department of Mathematics, University of Zagreb
2005
text
info:eu-repo/semantics/article
info:eu-repo/semantics/publishedVersion
application/pdf
https://hrcak.srce.hr/393
https://hrcak.srce.hr/file/937
Glasnik matematički
ISSN 0017-095X (Print)
ISSN 1846-7989 (Online)
Volume 40
Issue 1
eng
info:eu-repo/semantics/openAccess
oai:hrcak.srce.hr:394
2008-06-03
journal:27
A note on class number one criteria of Sirola for real quadratic fields
Walsh, P. G.
Quadratic field; Pellian equation
In a recent paper, Sirola gives two necessary and sufficient conditions for the class number of a real quadratic field to be equal to one. The purpose of this note is to remark that the equivalence of these conditions can be proved by using an elementary result of Nagell, which itself is a simple consequence of the fact that the Pell equation X2 - dY2 = 1 always has solutions in positive integers when d > 1 is squarefree.
Croatian Mathematical Society and Department of Mathematics, University of Zagreb
2005
text
info:eu-repo/semantics/article
info:eu-repo/semantics/publishedVersion
application/pdf
https://hrcak.srce.hr/394
https://hrcak.srce.hr/file/938
Glasnik matematički
ISSN 0017-095X (Print)
ISSN 1846-7989 (Online)
Volume 40
Issue 1
eng
info:eu-repo/semantics/openAccess
oai:hrcak.srce.hr:395
2008-06-03
journal:27
The θ-transfer technique: On Noetherian involution rings and symmetry of primitivity
Širola, Boris
Antihomomorphism; antiautomorphic ring; involution ring; θ-homomorphism; prime ideal; primitive ideal; symmetry of primitivity
Let : be a ring anti-isomorphism. We study -homomorphisms between left -modules E and right -modules M, that is, homomorphisms of the additive groups : E M satisfying (r.x) = (x).(r) for r and x E. We also study the class of Noetherian involution rings and the problem of symmetry of primitivity. In particular, suppose that for every semiprimitive Noetherian involution ring which has exactly two minimal prime ideals both of these satisfy (SP). Then every prime ideal of an arbitrary Noetherian ring satisfies (SP); we say that a prime ideal of some ring satisfies (SP), the symmetry of primitivity, if it holds that is left primitive if and only if it is right primitive. Besides, as an interesting fact, we note that any factor ring of the enveloping algebra of the Lie algebra (2) over a field of characteristic zero is an involution algebra, and so it satisfies the Krull symmetry.
Croatian Mathematical Society and Department of Mathematics, University of Zagreb
2005
text
info:eu-repo/semantics/article
info:eu-repo/semantics/publishedVersion
application/pdf
https://hrcak.srce.hr/395
https://hrcak.srce.hr/file/939
Glasnik matematički
ISSN 0017-095X (Print)
ISSN 1846-7989 (Online)
Volume 40
Issue 1
eng
info:eu-repo/semantics/openAccess
oai:hrcak.srce.hr:396
2008-06-03
journal:27
A note on generalized derivations of prime rings
Gusić, Ivica
Prime rings; homomorphisms; anti-homomorphisms
We show that a generalized derivation on a prime ring, that acts as a homomorphism or an anti-homomorphism on a non-zero ideal in the ring, is the zero map or the identity map.
Croatian Mathematical Society and Department of Mathematics, University of Zagreb
2005
text
info:eu-repo/semantics/article
info:eu-repo/semantics/publishedVersion
application/pdf
https://hrcak.srce.hr/396
https://hrcak.srce.hr/file/940
Glasnik matematički
ISSN 0017-095X (Print)
ISSN 1846-7989 (Online)
Volume 40
Issue 1
eng
info:eu-repo/semantics/openAccess
oai:hrcak.srce.hr:397
2008-06-03
journal:27
A property of groups of order ≤ pp(e+1) and exponent pe
Berkovich, Yakov
Pyramidal; regular; absolutely regular; irregular and metacyclic p-groups; p-groups of maximal class
Let G be a p-group of exponent pe and order pm, where m < p(e+1) if p > 2 and m 2(e+1) if p = 2. Then, if e-1(G) is irregular, then p = 2, e = 2 and e-1(G) D8 × C2, where |C2| = 2 and D8 is dihedral of order 8.
Croatian Mathematical Society and Department of Mathematics, University of Zagreb
2005
text
info:eu-repo/semantics/article
info:eu-repo/semantics/publishedVersion
application/pdf
https://hrcak.srce.hr/397
https://hrcak.srce.hr/file/941
Glasnik matematički
ISSN 0017-095X (Print)
ISSN 1846-7989 (Online)
Volume 40
Issue 1
eng
info:eu-repo/semantics/openAccess
oai:hrcak.srce.hr:398
2008-06-03
journal:27
Second-metacyclic finite 2-groups
Ćepulić, Vladimir
Ivanković, Marijana
Kovač Striko, Elizabeta
Finite group; p-group; metacyclic; second-maximal subgroup; second-metacyclic group
Second-metacyclic finite 2-groups are finite 2-groups with some non-metacyclic maximal subgroup and with all second-maximal subgroups being metacyclic. According to a known result there are only four non-metacyclic finite 2-groups with all maximal subgroups being metacyclic. The groups pointed in the title should contain some of these groups as a subgroup of index 2. There are seventeen second-maximal finite 2-groups, four among them being of order 16, ten of order 32 and three of order 64.
Croatian Mathematical Society and Department of Mathematics, University of Zagreb
2005
text
info:eu-repo/semantics/article
info:eu-repo/semantics/publishedVersion
application/pdf
https://hrcak.srce.hr/398
https://hrcak.srce.hr/file/942
Glasnik matematički
ISSN 0017-095X (Print)
ISSN 1846-7989 (Online)
Volume 40
Issue 1
eng
info:eu-repo/semantics/openAccess
oai:hrcak.srce.hr:399
2008-06-03
journal:27
Finite 2-groups G with |Ω2(G)| = 16
Janko, Zvonimir
2-group; metacyclic group; Frattini subgroup; self-centralizing subgroup
It is a known fact that the subgroup (G) generated by all elements of order at most 4 in a finite 2-group G has a strong influence on the structure of the whole group. Here we determine finite 2-groups G with |G| > 16 and (G) = 16. The resulting groups are only in one case metacyclic and we get in addition eight infinite classes of non-metacyclic 2-groups and one exceptional group of order 25. All non-metacyclic 2-groups will be given in terms of generators and relations.
In addition we determine completely finite 2-groups G which possess exactly one abelian subgroup of type (4,2).
Croatian Mathematical Society and Department of Mathematics, University of Zagreb
2005
text
info:eu-repo/semantics/article
info:eu-repo/semantics/publishedVersion
application/pdf
https://hrcak.srce.hr/399
https://hrcak.srce.hr/file/943
Glasnik matematički
ISSN 0017-095X (Print)
ISSN 1846-7989 (Online)
Volume 40
Issue 1
eng
info:eu-repo/semantics/openAccess
oai:hrcak.srce.hr:400
2008-06-03
journal:27
Approximation in Smirnov-Orlicz classes
Israfilov, Daniyal M.
Oktay, Burcin
Akgun, Ramazan
Dini-smooth curve; Smirnov-Orlicz classes; polynomial approximation; Faber polynomials; maximal convergence
We use the approximation properties of the Faber polynomials to obtain some direct theorems of the polynomial approximation in Smirnov-Orlicz classes.
Croatian Mathematical Society and Department of Mathematics, University of Zagreb
2005
text
info:eu-repo/semantics/article
info:eu-repo/semantics/publishedVersion
application/pdf
https://hrcak.srce.hr/400
https://hrcak.srce.hr/file/232
Glasnik matematički
ISSN 0017-095X (Print)
ISSN 1846-7989 (Online)
Volume 40
Issue 1
eng
info:eu-repo/semantics/openAccess
oai:hrcak.srce.hr:401
2008-06-03
journal:27
Global in time estimates for one-dimensional compressible viscous micropolar fluid model
Mujaković, Nermina
Micropolar fluid; strong solution; a priori estimates
An initial-boundary value 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 problem has a unique strong solution on ]0,1[ × ]0,T[, for each T > 0. Using this result we obtain a priori estimates for the solution independent of T.
Croatian Mathematical Society and Department of Mathematics, University of Zagreb
2005
text
info:eu-repo/semantics/article
info:eu-repo/semantics/publishedVersion
application/pdf
https://hrcak.srce.hr/401
https://hrcak.srce.hr/file/945
Glasnik matematički
ISSN 0017-095X (Print)
ISSN 1846-7989 (Online)
Volume 40
Issue 1
eng
info:eu-repo/semantics/openAccess
oai:hrcak.srce.hr:402
2008-06-03
journal:27
Delay dependent stability criterion for time discrete linear systems
Tang, X. H.
Cheng, S. S.
M-matrix; delay; stability
It is shown that every solution of the linear difference system with constant coefficients and delays tends to zero if a certain matrix derived from the coefficient matrix is a M-matrix and the diagonal delays satisfy delay dependent conditions.
Croatian Mathematical Society and Department of Mathematics, University of Zagreb
2005
text
info:eu-repo/semantics/article
info:eu-repo/semantics/publishedVersion
application/pdf
https://hrcak.srce.hr/402
https://hrcak.srce.hr/file/946
Glasnik matematički
ISSN 0017-095X (Print)
ISSN 1846-7989 (Online)
Volume 40
Issue 1
eng
info:eu-repo/semantics/openAccess
oai:hrcak.srce.hr:403
2008-06-03
journal:27
A remark on concentration of the error between a function and its polynomial approximants. II: A problem of Hasson
Wang, J. L.
Zhou, S. P.
Approximation; construction; Chebyshev polynomial
In the present paper we construct a function to give a positive answer to a problem raised by Hasson, that says, the conclusion of a result cannot be strengthened.
Croatian Mathematical Society and Department of Mathematics, University of Zagreb
2005
text
info:eu-repo/semantics/article
info:eu-repo/semantics/publishedVersion
application/pdf
https://hrcak.srce.hr/403
https://hrcak.srce.hr/file/947
Glasnik matematički
ISSN 0017-095X (Print)
ISSN 1846-7989 (Online)
Volume 40
Issue 1
eng
info:eu-repo/semantics/openAccess
oai:hrcak.srce.hr:404
2008-06-03
journal:27
Finite linear spaces consisting of two symmetric configurations
Krčadinac, Vedran
Šiftar, Juraj
Finite linear space; symmetric configuration
We investigate finite linear spaces consisting of two symmetric configurations. A construction method using projective planes is presented, giving a possibly infinite number of examples. Other examples are constructed by difference families and automorphism groups, including a complete classification of the smallest case. A question whether any Steiner 2-design with twice as many lines as points belongs to this family of linear spaces is raised, and answered in the affirmative for all known examples of such designs.
Croatian Mathematical Society and Department of Mathematics, University of Zagreb
2005
text
info:eu-repo/semantics/article
info:eu-repo/semantics/publishedVersion
application/pdf
https://hrcak.srce.hr/404
https://hrcak.srce.hr/file/948
Glasnik matematički
ISSN 0017-095X (Print)
ISSN 1846-7989 (Online)
Volume 40
Issue 1
eng
info:eu-repo/semantics/openAccess
oai:hrcak.srce.hr:405
2008-06-03
journal:27
Puppe exact sequence and its application in the fibrewise category map
Konami, Yoshifumi
Miwa, Takuo
Fibrewise topology; category MAP; fibrewise pointed homotopy; fibrewise pointed cofibration; Puppe exact sequence
In this paper, we study Puppe exact sequence and its application in the fibrewise category MAP. The application shows that we can prove the generalized formula for the suspension of fibrewise product spaces. Further, introducing an intermediate fibrewise category TOPHB, we give an another proof of the original formula in TOPB using the concepts of TOPHB.
Croatian Mathematical Society and Department of Mathematics, University of Zagreb
2005
text
info:eu-repo/semantics/article
info:eu-repo/semantics/publishedVersion
application/pdf
https://hrcak.srce.hr/405
https://hrcak.srce.hr/file/949
Glasnik matematički
ISSN 0017-095X (Print)
ISSN 1846-7989 (Online)
Volume 40
Issue 1
eng
info:eu-repo/semantics/openAccess
oai:hrcak.srce.hr:406
2008-06-03
journal:27
Harnack inequality for some discontinuous Markov processes with a diffusion part
Song, Renming
Vondraček, Zoran
Harnack inequality; harmonic functions; jump diffusion
In this paper we establish a Harnack inequality for nonnegative harmonic functions of some discontinuous Markov processes with a diffusion part.
Croatian Mathematical Society and Department of Mathematics, University of Zagreb
2005
text
info:eu-repo/semantics/article
info:eu-repo/semantics/publishedVersion
application/pdf
https://hrcak.srce.hr/406
https://hrcak.srce.hr/file/950
Glasnik matematički
ISSN 0017-095X (Print)
ISSN 1846-7989 (Online)
Volume 40
Issue 1
eng
info:eu-repo/semantics/openAccess
oai:hrcak.srce.hr:1242
2008-06-03
journal:27
Bounds for the size of sets with the property D(n)
Dujella, Andrej
Diophantine m-tuples; property D(n); large sieve
Let n be a nonzero integer and a1 < a2 < ... < am positive integers such that aiaj + n is a perfect square for all 1 ≤ i < j ≤ m. It is known that m ≤ 5 for n = 1. In this paper we prove that m ≤ 31 for |n| ≤ 400 and m < 15.476 log|n| for |n| > 400.
Croatian Mathematical Society and Department of Mathematics, University of Zagreb
2004
text
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info:eu-repo/semantics/publishedVersion
application/pdf
https://hrcak.srce.hr/1242
https://hrcak.srce.hr/file/2189
Glasnik matematički
ISSN 0017-095X (Print)
ISSN 1846-7989 (Online)
Volume 39
Issue 2
eng
info:eu-repo/semantics/openAccess
oai:hrcak.srce.hr:1243
2008-06-03
journal:27
Coproducts for Clifford algebras
Pandžić, Pavle
Clifford algebra; superalgebra; graded coproduct; coalgebra
We define a family of graded coproducts for Clifford algebras over finite dimensional real or complex vector spaces and study their basic properties.
Croatian Mathematical Society and Department of Mathematics, University of Zagreb
2004
text
info:eu-repo/semantics/article
info:eu-repo/semantics/publishedVersion
application/pdf
https://hrcak.srce.hr/1243
https://hrcak.srce.hr/file/2190
Glasnik matematički
ISSN 0017-095X (Print)
ISSN 1846-7989 (Online)
Volume 39
Issue 2
eng
info:eu-repo/semantics/openAccess
oai:hrcak.srce.hr:1244
2008-06-03
journal:27
On a lemma of Thompson
Berkovich, Yakov
Solvable extraspecial, special and metacyclic p-groups; Blackburn's theorem; the stabilizer of a chain
In Theorem 3 we improve a lemma of Thompson omitting one of its conditions. In that lemma the structure of T, a Sylow 2-subgroup of G, is described only. In contrast to that lemma, we describe in detail the structure of the whole group G and embedding of T in G. In Theorem 4 we consider a similar, but more general, situation for groups of odd order.
Croatian Mathematical Society and Department of Mathematics, University of Zagreb
2004
text
info:eu-repo/semantics/article
info:eu-repo/semantics/publishedVersion
application/pdf
https://hrcak.srce.hr/1244
https://hrcak.srce.hr/file/2191
Glasnik matematički
ISSN 0017-095X (Print)
ISSN 1846-7989 (Online)
Volume 39
Issue 2
eng
info:eu-repo/semantics/openAccess
oai:hrcak.srce.hr:1245
2008-06-03
journal:27
Minimal nonmodular finite p-groups
Janko, Zvonimir
p-group; modular group; nonmodular group; quaternion group; minimal nonabelian group
We describe first the structure of finite minimal nonmodular 2-groups G. We show that in case |G| > 25, each proper subgroup of G is Q8-free and G/(G) is minimal nonabelian of order 24 or 25. If |G/(G)| = 24, then the structure of G is determined up to isomorphism (Propositions 2.4 and 2.5). If |G/(G)| = 25, then (G) E8 and G/(G) is metacyclic (Theorem 2.8).
Then we classify finite minimal nonmodular p-groups G with p > 2 and |G| > p4 (Theorems 3.5 and 3.7). We show that G/(G) is nonabelian of order p3 and exponent p and (G) is metacyclic. Also, G/(G) Ep and G/(G) is metacyclic.
Croatian Mathematical Society and Department of Mathematics, University of Zagreb
2004
text
info:eu-repo/semantics/article
info:eu-repo/semantics/publishedVersion
application/pdf
https://hrcak.srce.hr/1245
https://hrcak.srce.hr/file/2192
Glasnik matematički
ISSN 0017-095X (Print)
ISSN 1846-7989 (Online)
Volume 39
Issue 2
eng
info:eu-repo/semantics/openAccess
oai:hrcak.srce.hr:1246
2008-06-03
journal:27
2-groups with a self-centralizing abelian subgroup of type (4,2)
Janko, Zvonimir
Finite 2-groups; self-centralizing subgroups; Frattini subgroups; minimal nonabelian 2-groups; dihedral; semi-dihedral; generalized quaternian 2-groups
In this paper we classify finite 2-groups G which possess a self-centralizing abelian subgroup A of type (4,2). In the difficult case, where A is contained in the Frattini subgroup (G), we describe the structure of the group G in great detail. In the other case, where A (G), there is an open problem.
Croatian Mathematical Society and Department of Mathematics, University of Zagreb
2004
text
info:eu-repo/semantics/article
info:eu-repo/semantics/publishedVersion
application/pdf
https://hrcak.srce.hr/1246
https://hrcak.srce.hr/file/2193
Glasnik matematički
ISSN 0017-095X (Print)
ISSN 1846-7989 (Online)
Volume 39
Issue 2
eng
info:eu-repo/semantics/openAccess
oai:hrcak.srce.hr:1247
2008-06-03
journal:27
Constrained abstract representation problems in semigroups and partial groupoids
Mani, A.
Constrained abstract representation problems; retracts; retract extensions; partial semigroups; partial groupoids; generalized periodic semigroups; CSM-types
In this paper different constrained abstract representation theorems for partial groupoids and semigroups are proved. Methods for improving the retract properties of the structures are also developed. These have strong class-theoretical implications for many types of generalized periodic semigroups and related partial semigroups. The results are significant in a model-theoretical setting.
Croatian Mathematical Society and Department of Mathematics, University of Zagreb
2004
text
info:eu-repo/semantics/article
info:eu-repo/semantics/publishedVersion
application/pdf
https://hrcak.srce.hr/1247
https://hrcak.srce.hr/file/2194
Glasnik matematički
ISSN 0017-095X (Print)
ISSN 1846-7989 (Online)
Volume 39
Issue 2
eng
info:eu-repo/semantics/openAccess
oai:hrcak.srce.hr:1248
2008-06-03
journal:27
On Landau's theorems
Mitrinović, Dragoslav S.
Pečarić, Josip E.
Kraljević, Hrvoje
Differentiable functions; Frechet-differentiability; Landau's inequalities
In this paper we give some applications and special cases of a generalization of the Landau's theorem for Frechet-differentiable functions.
Croatian Mathematical Society and Department of Mathematics, University of Zagreb
2004
text
info:eu-repo/semantics/article
info:eu-repo/semantics/publishedVersion
application/pdf
https://hrcak.srce.hr/1248
https://hrcak.srce.hr/file/2195
Glasnik matematički
ISSN 0017-095X (Print)
ISSN 1846-7989 (Online)
Volume 39
Issue 2
eng
info:eu-repo/semantics/openAccess
oai:hrcak.srce.hr:1249
2008-06-03
journal:27
On the linear combination of the representations of starlikeness and convexity
Tuneski, Nikola
Aceska, Roza
Starlike function; starlike function of order α; criteria; differential subordination; Jack lemma
Let be the class of analytic functions in the unit disk U = {z : |z| < 1} that are normalized with f(0) = f'(0) - 1 = 0. Also, let S*[A,B], -1 ≤ B < A ≤ 1, be the class of functions f , such that zf'(z) / f(z) (1 + Az) / (1 + Bz), where "" denotes the usual subordination. In this paper we investigate the linear combination of the analytic representations of starlikeness and convexity and give sharp sufficient conditions over the differential operator
a zf'(z) / f(z) + b (1 + zf''(z) / f'(z))
that imply f S*[A,B]. In that purpose we use the method of differential subordinations. Several corollaries and examples for different choices of A, B, a and b are given and comparison with previous known results is done.
Croatian Mathematical Society and Department of Mathematics, University of Zagreb
2004
text
info:eu-repo/semantics/article
info:eu-repo/semantics/publishedVersion
application/pdf
https://hrcak.srce.hr/1249
https://hrcak.srce.hr/file/2196
Glasnik matematički
ISSN 0017-095X (Print)
ISSN 1846-7989 (Online)
Volume 39
Issue 2
eng
info:eu-repo/semantics/openAccess
oai:hrcak.srce.hr:1250
2008-06-03
journal:27
Estimates on the Dirichlet heat kernel of domains above the graphs of bounded C1,1 functions
Song, Renming
Dirichlet heat kernels; Green functions; killed Brownian motions
Suppose that D is the domain in , d ≥ 3, above the graph of a bounded C1,1 function : and that pD(t, x, y) is the Dirichlet heat kernel in D. In this paper we show that there exist positive constants C1, C2, C3, C4 such that for all t > 0 and x, y D,
C1((x)(y) / t 1) t -d/2 e -C|x-y|^2 / t ≤ pD(t, x, y),
pD(t, x, y) ≤ C3((x)(y) / t 1) t -d/2 e -C|x-y|^2 / t,
where (x) stands for the distance between x and D.
Croatian Mathematical Society and Department of Mathematics, University of Zagreb
2004
text
info:eu-repo/semantics/article
info:eu-repo/semantics/publishedVersion
application/pdf
https://hrcak.srce.hr/1250
https://hrcak.srce.hr/file/2197
Glasnik matematički
ISSN 0017-095X (Print)
ISSN 1846-7989 (Online)
Volume 39
Issue 2
eng
info:eu-repo/semantics/openAccess
oai:hrcak.srce.hr:1251
2008-06-03
journal:27
Oscillation of higher order difference equations via comparison
Agarwal, Ravi P.
Grace, Said R.
O'Regan, Donal
Oscillation; nonoscillation; difference; nonlinear; comparison
In this paper we shall present some new oscillation criteria for difference equations of the form
x(n) + q(n)f(x[n - ]) = 0
and
x(n) = q(t)f(x[n - ]) + p(n)F(x[n + ])
via comparison with some difference equations of lower order whose oscillatory behavior are known.
Croatian Mathematical Society and Department of Mathematics, University of Zagreb
2004
text
info:eu-repo/semantics/article
info:eu-repo/semantics/publishedVersion
application/pdf
https://hrcak.srce.hr/1251
https://hrcak.srce.hr/file/2198
Glasnik matematički
ISSN 0017-095X (Print)
ISSN 1846-7989 (Online)
Volume 39
Issue 2
eng
info:eu-repo/semantics/openAccess
oai:hrcak.srce.hr:1252
2008-06-03
journal:27
Bounded 2-linear operators on 2-normed sets
Lewandowska, Zofia
2-normed set; 2-normed space; bounded 2-linear operator; Banach-Steinhaus theorems
In this paper properties of bounded 2-linear operators from a 2-normed set into a normed space are considered. The space of these operators is a Banach space and a symmetric 2-normed space. In the third part we will formulate Banach-Steinhaus Theorems for a family of bounded 2-linear operators from a 2-normed set into a Banach space.
Croatian Mathematical Society and Department of Mathematics, University of Zagreb
2004
text
info:eu-repo/semantics/article
info:eu-repo/semantics/publishedVersion
application/pdf
https://hrcak.srce.hr/1252
https://hrcak.srce.hr/file/2199
Glasnik matematički
ISSN 0017-095X (Print)
ISSN 1846-7989 (Online)
Volume 39
Issue 2
eng
info:eu-repo/semantics/openAccess
oai:hrcak.srce.hr:1253
2008-06-03
journal:27
A note on extensions of Hilbert C*-modules and their morphisms
Bruckler, Franka Miriam
Hilbert C*-module; operator space; extension; multiplier algebra; completely bounded map
The aim of this paper is to connect the results of D. Bakic and B. Guljas about C*-extensions of Hilbert C*-modules with results of D. P. Blecher about Hilbert C*-extensions of operator spaces. In the first part, we give conditions on a completely bounded linear operator between Hilbert C*-modules for the possibility of extending the operator to a "corner-preserving" C*-morphism of the corresponding linking-algebras (or, equivalently, for the operator being a Hilbert C*-morphism). The second part provides an order preserving bijection between the sets of C*-extensions of a Hilbert C*-module and its Hilbert C*-extensions, the latter being a generalized version of Blecher's Hilbert C*-extensions of operator spaces.
Croatian Mathematical Society and Department of Mathematics, University of Zagreb
2004
text
info:eu-repo/semantics/article
info:eu-repo/semantics/publishedVersion
application/pdf
https://hrcak.srce.hr/1253
https://hrcak.srce.hr/file/2200
Glasnik matematički
ISSN 0017-095X (Print)
ISSN 1846-7989 (Online)
Volume 39
Issue 2
eng
info:eu-repo/semantics/openAccess
oai:hrcak.srce.hr:1254
2008-06-03
journal:27
Unit-sphere preserving mappings
Jung, Soon-Mo
Kim, Byungbae
Isometry; unit-circle preserving mapping
We prove that if a one-to-one mapping f : (n ≥ 2) preserves the unit n - 1 spheres (Sn -1), then f is a linear isometry up to translation.
Croatian Mathematical Society and Department of Mathematics, University of Zagreb
2004
text
info:eu-repo/semantics/article
info:eu-repo/semantics/publishedVersion
application/pdf
https://hrcak.srce.hr/1254
https://hrcak.srce.hr/file/2201
Glasnik matematički
ISSN 0017-095X (Print)
ISSN 1846-7989 (Online)
Volume 39
Issue 2
eng
info:eu-repo/semantics/openAccess
oai:hrcak.srce.hr:1255
2008-06-03
journal:27
A selection theorem for simplex-valued maps
Ivanšić, Ivan
Rubin, Leonard R.
Contiguous functions; continuous function; hereditarily paracompact; polyhedron; selection; simplex; simplicial complex; stratifiable space
The purpose of this short note is to prove the following theorem. Let X be a hereditarily normal paracompact Hausdorff space, K be a simplicial complex, and : X K be a function. Suppose that {U | } and {f | } are collections such that for each , f is a map of U to |K|, and if x U, then f(x) (x). Assume further that {U | } is an open cover of X. Then there exists a map f : X |K| such that for each x X, f(x) (x).
Croatian Mathematical Society and Department of Mathematics, University of Zagreb
2004
text
info:eu-repo/semantics/article
info:eu-repo/semantics/publishedVersion
application/pdf
https://hrcak.srce.hr/1255
https://hrcak.srce.hr/file/2202
Glasnik matematički
ISSN 0017-095X (Print)
ISSN 1846-7989 (Online)
Volume 39
Issue 2
eng
info:eu-repo/semantics/openAccess
oai:hrcak.srce.hr:1256
2008-06-03
journal:27
Extension dimension of inverse limits. Correction of a proof
Mardešić, Sibe
Polyhedron; inverse limit; extension dimension
The erroneous proof of a lemma in a previous paper of the author on extension dimension of inverse limits is replaced by a correct one.
Croatian Mathematical Society and Department of Mathematics, University of Zagreb
2004
text
info:eu-repo/semantics/article
info:eu-repo/semantics/publishedVersion
application/pdf
https://hrcak.srce.hr/1256
https://hrcak.srce.hr/file/2203
Glasnik matematički
ISSN 0017-095X (Print)
ISSN 1846-7989 (Online)
Volume 39
Issue 2
eng
info:eu-repo/semantics/openAccess
oai:hrcak.srce.hr:1257
2008-06-03
journal:27
A note on permeability for a network of thin channels
Marušić, Sanja
Periodic porous media; network of thin channels; commuting limits
We study a viscous flow through a periodic network of thin channels with small period and small thickness . We consider two cases limε --> 0 (limδ --> 0) and limδ --> 0 (limε --> 0). In both cases the limit (homogenized) problem is the Darcy law with the same permeability tensor.
Croatian Mathematical Society and Department of Mathematics, University of Zagreb
2004
text
info:eu-repo/semantics/article
info:eu-repo/semantics/publishedVersion
application/pdf
https://hrcak.srce.hr/1257
https://hrcak.srce.hr/file/2204
Glasnik matematički
ISSN 0017-095X (Print)
ISSN 1846-7989 (Online)
Volume 39
Issue 2
eng
info:eu-repo/semantics/openAccess
oai:hrcak.srce.hr:1258
2008-06-03
journal:27
Some remarks on the category SET(L), part III
Solovyov, Sergey A.
L-set; category of L-subsets of sets; topological construct; topos; special morphism; special object
This paper considers the category SET(L) of L-subsets of sets with a fixed basis L and is a continuation of our previous investigation of this category. Here we study its general properties (e.g., we derive that the category is a topological construct) as well as some of its special objects and morphisms.
Croatian Mathematical Society and Department of Mathematics, University of Zagreb
2004
text
info:eu-repo/semantics/article
info:eu-repo/semantics/publishedVersion
application/pdf
https://hrcak.srce.hr/1258
https://hrcak.srce.hr/file/2205
Glasnik matematički
ISSN 0017-095X (Print)
ISSN 1846-7989 (Online)
Volume 39
Issue 1
eng
info:eu-repo/semantics/openAccess
oai:hrcak.srce.hr:1259
2008-06-03
journal:27
A remark on centralizers in semiprime rings
Kosi-Ulbl, Irena
Prime ring; semiprime ring; left (right) centralizer; left (right) Jordan centralizer; centralizer
The purpose of this paper is to prove the following result: Let m 1, n 1 be fixed integers and let R be a (m + n + 2)!-torsion free semiprime ring with the identity element. Suppose there exists an additive mapping T : R R, such that
T(xm+n+1) = xm T(x) xn
holds for all x R. In this case T is a centralizer.
Croatian Mathematical Society and Department of Mathematics, University of Zagreb
2004
text
info:eu-repo/semantics/article
info:eu-repo/semantics/publishedVersion
application/pdf
https://hrcak.srce.hr/1259
https://hrcak.srce.hr/file/2206
Glasnik matematički
ISSN 0017-095X (Print)
ISSN 1846-7989 (Online)
Volume 39
Issue 1
eng
info:eu-repo/semantics/openAccess
oai:hrcak.srce.hr:1260
2008-06-03
journal:27
On generalized derivations as homomorphisms and anti-homomorphisms
Rehman, Nadeem-úr
Prime rings; generalized derivations; torsion free rings; homomorphisms and anti-homomorphisms
The concept of derivations as well as generalized derivations (i.e. Ia,b(x) = ax + xb, for all a,b R) have been generalized as an additive function F : R R satisfying F(xy) = F(x)y + xd(y) for all x,y R, where d is a nonzero derivation on R. Such a function F is said to be a generalized derivation. In the present paper it is shown that: if R is 2-torsion free prime ring, I 0 an ideal of R and F a generalized derivation of R such that either F(xy) = F(x)F(y) or F(xy) = F(y)F(x) for all x,y I, then R is commutative.
Croatian Mathematical Society and Department of Mathematics, University of Zagreb
2004
text
info:eu-repo/semantics/article
info:eu-repo/semantics/publishedVersion
application/pdf
https://hrcak.srce.hr/1260
https://hrcak.srce.hr/file/2207
Glasnik matematički
ISSN 0017-095X (Print)
ISSN 1846-7989 (Online)
Volume 39
Issue 1
eng
info:eu-repo/semantics/openAccess
oai:hrcak.srce.hr:1261
2008-06-03
journal:27
R groups for quaternionic hermitian groups
Hanzer, Marcela
R groups; p-adic groups
In this paper a complete classification of R-groups for hermitian quaternionic groups is given. This completes the work of Goldberg for all classical p-adic groups. As a consequence, multiplicity one result follows.
Croatian Mathematical Society and Department of Mathematics, University of Zagreb
2004
text
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info:eu-repo/semantics/publishedVersion
application/pdf
https://hrcak.srce.hr/1261
https://hrcak.srce.hr/file/2208
Glasnik matematički
ISSN 0017-095X (Print)
ISSN 1846-7989 (Online)
Volume 39
Issue 1
eng
info:eu-repo/semantics/openAccess
oai:hrcak.srce.hr:1262
2008-06-03
journal:27
Sur une conjecture de Tadic
Badulescu, A. I.
Renard, D. A.
Representations of p-adic groups; unitary dual
Let F be a non-archimedian field of characteristic zero and D a central division algebra over F of finite dimension d2. For all positive integer r, set G'r = GL(r,D).
In 1990, M. Tadic gave a conjectural classification of the unitary dual of the G'r, and five statements denoted U0, ... , U4, which imply the classification. M. Tadic proved U3 and U4. Also, U0 and U1 imply U2. These statements, and the resulting classification are the natural generalization of the case D = F completely solved by M. Tadic in 1986. Here we prove U1. Thus, the classification of the unitary dual of the G'r is now reduced to the conjecture U0, which states that a parabolically induced representation from an irreducible unitary representation is irreducible.
Croatian Mathematical Society and Department of Mathematics, University of Zagreb
2004
text
info:eu-repo/semantics/article
info:eu-repo/semantics/publishedVersion
application/pdf
https://hrcak.srce.hr/1262
https://hrcak.srce.hr/file/2209
Glasnik matematički
ISSN 0017-095X (Print)
ISSN 1846-7989 (Online)
Volume 39
Issue 1
eng
info:eu-repo/semantics/openAccess
oai:hrcak.srce.hr:1263
2008-06-03
journal:27
Loewner chains and parametric representation of biholomorphic mappings in complex Banach spaces
Hamada, Hidetaka
Kohr, Gabriela
Biholomorphic mapping; Loewner chains; parametric representation; univalence criteria
Let X be a complex Banach space and let B be the unit ball of X. In this paper we obtain sufficient conditions for biholomorphic mappings on B to have parametric representation. Also we study certain properties of Loewner chains, and we obtain infinite dimensional versions of some well known univalence criteria on the unit ball of .
Croatian Mathematical Society and Department of Mathematics, University of Zagreb
2004
text
info:eu-repo/semantics/article
info:eu-repo/semantics/publishedVersion
application/pdf
https://hrcak.srce.hr/1263
https://hrcak.srce.hr/file/2210
Glasnik matematički
ISSN 0017-095X (Print)
ISSN 1846-7989 (Online)
Volume 39
Issue 1
eng
info:eu-repo/semantics/openAccess
oai:hrcak.srce.hr:1264
2008-06-03
journal:27
A comparison result for a linear differential equation with piecewise constant delay
Nieto, Juan J.
Differential inequalities; functional differential equations; piecewise constant delay; periodic boundary conditions
We present a new comparison result for an equation of the form
u'(t) + m u(t) + n u([t]) = (t), t [0,T]
where [ ] denotes the greatest integer function.
Croatian Mathematical Society and Department of Mathematics, University of Zagreb
2004
text
info:eu-repo/semantics/article
info:eu-repo/semantics/publishedVersion
application/pdf
https://hrcak.srce.hr/1264
https://hrcak.srce.hr/file/2211
Glasnik matematički
ISSN 0017-095X (Print)
ISSN 1846-7989 (Online)
Volume 39
Issue 1
eng
info:eu-repo/semantics/openAccess
oai:hrcak.srce.hr:1265
2008-06-03
journal:27
Derivation of the Reynolds type equation with memory effects, governing transient flow of lubric
Duvnjak, Antonija
Nonstationary Stokes system; nonlocal Reynolds equation
In this paper we derive the Reynolds type lubrication equation with memory effects for lubrication of a rotating shaft. Starting from the nonstationary Stokes equations and using the asymptotic expansion we obtain a law that is nonlocal in time and gives a linear connection between velocity and pressure gradient. Our law tends to the classical Reynolds equation when time tends to infinity. We prove a convergence theorem for velocity and pressure in appropriate functional space.
Croatian Mathematical Society and Department of Mathematics, University of Zagreb
2004
text
info:eu-repo/semantics/article
info:eu-repo/semantics/publishedVersion
application/pdf
https://hrcak.srce.hr/1265
https://hrcak.srce.hr/file/2212
Glasnik matematički
ISSN 0017-095X (Print)
ISSN 1846-7989 (Online)
Volume 39
Issue 1
eng
info:eu-repo/semantics/openAccess
oai:hrcak.srce.hr:1266
2008-06-03
journal:27
Statistical (T) rates of convergence
Miller, H. I.
Orhan, C.
Natural density; statistically convergent sequence; rate of convergence
The basis for comparing rates of convergence of two null sequences is that "x = (xn) converges (stat T) faster than z = (zn) provided that (xn/zn) is T-statistically convergent to zero" where T = (tmn) is a mean. In this paper we extend the previously known results either on the ordinary convergence or statistical rates of convergence of two null sequences. We also consider lacunary statistical rates of convergence.
Croatian Mathematical Society and Department of Mathematics, University of Zagreb
2004
text
info:eu-repo/semantics/article
info:eu-repo/semantics/publishedVersion
application/pdf
https://hrcak.srce.hr/1266
https://hrcak.srce.hr/file/2213
Glasnik matematički
ISSN 0017-095X (Print)
ISSN 1846-7989 (Online)
Volume 39
Issue 1
eng
info:eu-repo/semantics/openAccess
oai:hrcak.srce.hr:1267
2008-06-03
journal:27
Nonseparable Walsh-type functions on Rd
Nielsen, Morten
Walsh functions; nonstationary wavelet packets; nonseparable wavelet systems; pointwise convergence a.e
We study wavelet packets in the setting of a multiresolution analysis of L2() generated by an arbitrary dilation matrix A satisfying |det A| = 2. In particular, we consider the wavelet packets associated with a multiresolution analysis with a scaling function given by the characteristic function of some set (called a tile) in . The functions in this class of wavelet packets are called generalized Walsh functions, and it is proved that the new functions share two major convergence properties with the Walsh system defined on [0,1). The functions constitute a Schauder basis for Lp(), 1 < p < , and the expansion of Lp-functions converge pointwise almost everywhere. Finally, we introduce a family of compactly supported wavelet packets in of class Cr(), 1 r < , modeled after the generalized Walsh function. It is proved that this class of smooth wavelet packets has the same convergence properties as the generalized Walsh functions.
Croatian Mathematical Society and Department of Mathematics, University of Zagreb
2004
text
info:eu-repo/semantics/article
info:eu-repo/semantics/publishedVersion
application/pdf
https://hrcak.srce.hr/1267
https://hrcak.srce.hr/file/2214
Glasnik matematički
ISSN 0017-095X (Print)
ISSN 1846-7989 (Online)
Volume 39
Issue 1
eng
info:eu-repo/semantics/openAccess
oai:hrcak.srce.hr:1268
2008-06-03
journal:27
On directly additive selectors for convex and star bodies
Moszynska, Maria
Convex bodies; star bodies; selectors; direct sum
The paper deals with direct additivity of selectors, as well for convex as for star bodies. Sections 3 and 4 concern selectors for convex bodies. In Section 5 two methods of extending a selector for convex bodies to a selector for star bodies are considered, both preserving direct additivity.
Croatian Mathematical Society and Department of Mathematics, University of Zagreb
2004
text
info:eu-repo/semantics/article
info:eu-repo/semantics/publishedVersion
application/pdf
https://hrcak.srce.hr/1268
https://hrcak.srce.hr/file/2215
Glasnik matematički
ISSN 0017-095X (Print)
ISSN 1846-7989 (Online)
Volume 39
Issue 1
eng
info:eu-repo/semantics/openAccess
oai:hrcak.srce.hr:1269
2008-06-03
journal:27
On rectangular inverse systems of topological spaces
Mardešić, Sibe
Inverse system; rectangular inverse system; inverse limit; iterated inverse limit; compact Hausdorff space; compact metric space; polyhedron; ANR
For every cofinite inverse system of compact Hausdorff spaces X = (X, p', ), there exists a cofinite inverse system of compact polyhedra Z = (Z, r'', × T) and there are mappings u : X Z, (, ) × T, such that u p' = r'' u', for '. Moreover, for every , the mapping u : X Z = (Z, r'', T), given by the mappings u', T, is a limit of Z. If mappings p : X X form a limit p : X X, then the mappings v = u p : X Z form a limit v : X Z. An analogous result holds for cofinite inverse systems of topological spaces and ANR-resolutions (polyhedral resolutions).
Croatian Mathematical Society and Department of Mathematics, University of Zagreb
2004
text
info:eu-repo/semantics/article
info:eu-repo/semantics/publishedVersion
application/pdf
https://hrcak.srce.hr/1269
https://hrcak.srce.hr/file/2216
Glasnik matematički
ISSN 0017-095X (Print)
ISSN 1846-7989 (Online)
Volume 39
Issue 1
eng
info:eu-repo/semantics/openAccess
oai:hrcak.srce.hr:1270
2008-06-03
journal:27
A generalization of the 0-numerical range
Rajić, Rajna
q-numerical range of an operator
Let H be a complex Hilbert space. Given a bounded linear operator A on H, we describe the set
Rn(A) = {V*AW : V,W : H, V*V = W*W = In, V*W = 0}.
It is shown that the closed matricial convex hull of Rn(A) is a closed ball of radius
min {|A - I| : }
centered at the origin.
Croatian Mathematical Society and Department of Mathematics, University of Zagreb
2004
text
info:eu-repo/semantics/article
info:eu-repo/semantics/publishedVersion
application/pdf
https://hrcak.srce.hr/1270
https://hrcak.srce.hr/file/2217
Glasnik matematički
ISSN 0017-095X (Print)
ISSN 1846-7989 (Online)
Volume 39
Issue 1
eng
info:eu-repo/semantics/openAccess
oai:hrcak.srce.hr:1271
2008-06-03
journal:27
Spans of continua related to indented circles
West, Thelma
Continua; simple closed curves; indented circles
Let X be a special type of simple closed curve in the plane known as an indented circle. Let Y be a continuum which is contained in X V. where V is the bounded component of X. We show that (Y) (X) where is the span , surjective span *, semispan , surjective semispan *, symmetric span s or the surjective symmetric span s*.
Croatian Mathematical Society and Department of Mathematics, University of Zagreb
2004
text
info:eu-repo/semantics/article
info:eu-repo/semantics/publishedVersion
application/pdf
https://hrcak.srce.hr/1271
https://hrcak.srce.hr/file/2218
Glasnik matematički
ISSN 0017-095X (Print)
ISSN 1846-7989 (Online)
Volume 39
Issue 1
eng
info:eu-repo/semantics/openAccess
oai:hrcak.srce.hr:1272
2008-06-03
journal:27
Some questions of equivariant movability
Gevorgyan, P. S.
Equivariant shape theory; equivariant movability
In this article some questions of equivariant movability, connected with the substitution of the acting group G on closed subgroup H and with transitions to spaces of H-orbits and H-fixed points spaces, are investigated. In a special case, the characterization of equivariantly movable G-spaces is given.
Croatian Mathematical Society and Department of Mathematics, University of Zagreb
2004
text
info:eu-repo/semantics/article
info:eu-repo/semantics/publishedVersion
application/pdf
https://hrcak.srce.hr/1272
https://hrcak.srce.hr/file/2219
Glasnik matematički
ISSN 0017-095X (Print)
ISSN 1846-7989 (Online)
Volume 39
Issue 1
eng
info:eu-repo/semantics/openAccess
oai:hrcak.srce.hr:1315
2008-06-03
journal:27
2-(56,12,3) designs and their class graphs
Rukavina, Sanja
Residual design; automorphism group; class graph
There exist exactly 1122 pairwise non-isomorphic 2-(56,12,3) designs being the residual designs of the known symmetric (71,15,3) designs. Six pairwise non-isomorphic strongly regular graphs with parameters (35,16,6,8) were constructed as class graphs of the obtained residual designs. Orders of the full automorphism groups of these graphs are 12, 32, 96, 192, 288 and 40320.
Croatian Mathematical Society and Department of Mathematics, University of Zagreb
2003
text
info:eu-repo/semantics/article
info:eu-repo/semantics/publishedVersion
application/pdf
https://hrcak.srce.hr/1315
https://hrcak.srce.hr/file/2285
Glasnik matematički
ISSN 0017-095X (Print)
ISSN 1846-7989 (Online)
Volume 38
Issue 2
eng
info:eu-repo/semantics/openAccess
oai:hrcak.srce.hr:1316
2008-06-03
journal:27
Mix-decomposition of the complete graph into directed factors of diameter 2 and undirected factors of diameter 3
Vukičević, Damir
Decomposition; mix-decomposition; factor; graph
We estimate the values, for each k, of the smallest n such that Kn can be mix-decomposed into k undirected factors of diameter 3 and one directed factor of diameter 2. We find the asymptotic value of ratio of n and k, when k tends to infinity and generalize this result for mix-decompositions into p directed factors of diameter 2 and k undirected factors of diameter 3.
Croatian Mathematical Society and Department of Mathematics, University of Zagreb
2003
text
info:eu-repo/semantics/article
info:eu-repo/semantics/publishedVersion
application/pdf
https://hrcak.srce.hr/1316
https://hrcak.srce.hr/file/2286
Glasnik matematički
ISSN 0017-095X (Print)
ISSN 1846-7989 (Online)
Volume 38
Issue 2
eng
info:eu-repo/semantics/openAccess
oai:hrcak.srce.hr:1317
2008-06-03
journal:27
Polynomial-exponential equations and linear recurrences
Fuchs, Clemens
Polynomial-exponential equations; linear recurrences; Subspace-Theorem
Let K be an algebraic number field and let (Gn) be a linear recurring sequence defined by
Gn = + P2(n) + ... + Pt(n) ,
where , , ... , are non-zero elements of K and where Pi(x) K[x] for i = 2, ... , t. Furthermore let f(z,x) K[z,x] monic in x. In this paper we want to study the polynomial-exponential Diophantine equation f(Gn,x)=0. We want to use a quantitative version of W. M. Schmidt's Subspace Theorem (due to J.-H. Evertse) to calculate an upper bound for the number of solutions (n,x) under some additional assumptions.
Croatian Mathematical Society and Department of Mathematics, University of Zagreb
2003
text
info:eu-repo/semantics/article
info:eu-repo/semantics/publishedVersion
application/pdf
https://hrcak.srce.hr/1317
https://hrcak.srce.hr/file/2287
Glasnik matematički
ISSN 0017-095X (Print)
ISSN 1846-7989 (Online)
Volume 38
Issue 2
eng
info:eu-repo/semantics/openAccess
oai:hrcak.srce.hr:1318
2008-06-03
journal:27
An equation related to centralizers in semiprime rings
Vukman, Joso
Kosi-Ulbl, Irena
Prime ring; semiprime ring; derivation; Jordan derivation; Jordan triple derivation; left (right) centralizer; left (right) Jordan centralizer; centralizer
Let R be a 2-torsion free semiprime ring with extended centroid C and let T : R R be an additive mapping. Suppose that 3T(xyx) = T(x)yx + xT(y)x + xyT(x) holds for all x,y R. Then there exists an element C such that T(x) = x for all x R.
Croatian Mathematical Society and Department of Mathematics, University of Zagreb
2003
text
info:eu-repo/semantics/article
info:eu-repo/semantics/publishedVersion
application/pdf
https://hrcak.srce.hr/1318
https://hrcak.srce.hr/file/2288
Glasnik matematički
ISSN 0017-095X (Print)
ISSN 1846-7989 (Online)
Volume 38
Issue 2
eng
info:eu-repo/semantics/openAccess
oai:hrcak.srce.hr:1319
2008-06-03
journal:27
The DeMeyer-Kanzaki Galois extension and its skew group ring
Szeto, George
Xue, Lianyong
Galois extensions; DeMeyer-Kanzaki Galois extensions; commutative Galois algebras; Azumaya algebras; H-separable extensions; skew group rings
Several characterizations are given for a ring B being a DeMeyer-Kanzaki Galois extension with Galois group G in terms of the skew group ring B * G. Consequently, the results of S. Ikehata on commutative Galois algebras are generalized.
Croatian Mathematical Society and Department of Mathematics, University of Zagreb
2003
text
info:eu-repo/semantics/article
info:eu-repo/semantics/publishedVersion
application/pdf
https://hrcak.srce.hr/1319
https://hrcak.srce.hr/file/2289
Glasnik matematički
ISSN 0017-095X (Print)
ISSN 1846-7989 (Online)
Volume 38
Issue 2
eng
info:eu-repo/semantics/openAccess
oai:hrcak.srce.hr:1320
2008-06-03
journal:27
A generalization of a result on maximum modulus of polynomials
Jain, V. K.
Polynomials; zeros; geometric mean; maximum modulus
For an arbitrary entire function f(z)$, let M(f,d) = max|z|=d |f(z)|. It is known that if the geometric mean of the moduli of the zeros of a polynomial p(z) of degree n is at least 1, and M(p,1) = 1, then for R > 1, M(p,R) R/2 + 1/2 if n = 1,
M(p,R) Rn/2 + (3+22)Rn-2/2 if n 2.
We have obtained a generalization of this result, by assuming the geometric mean of the moduli of the zeros of the polynomial to be at least k, (k > 0).
Croatian Mathematical Society and Department of Mathematics, University of Zagreb
2003
text
info:eu-repo/semantics/article
info:eu-repo/semantics/publishedVersion
application/pdf
https://hrcak.srce.hr/1320
https://hrcak.srce.hr/file/2290
Glasnik matematički
ISSN 0017-095X (Print)
ISSN 1846-7989 (Online)
Volume 38
Issue 2
eng
info:eu-repo/semantics/openAccess
oai:hrcak.srce.hr:1321
2008-06-03
journal:27
Triple solutions for the one-dimensional p-Laplacian
Lu, Haishen
O'Regan, Donal
Agarwal, Ravi P.
Lower and upper solutions; three solutions; p-Laplace equation; Nagumo condition
We give conditions on f involving pairs of lower and upper solutions which lead to the existence of at least three solutions to the two point boundary value problem
(|u'|p -2 u') = q(t) f(t,u,u') on (0,1), u(0) = u(1) = 0.
Croatian Mathematical Society and Department of Mathematics, University of Zagreb
2003
text
info:eu-repo/semantics/article
info:eu-repo/semantics/publishedVersion
application/pdf
https://hrcak.srce.hr/1321
https://hrcak.srce.hr/file/2291
Glasnik matematički
ISSN 0017-095X (Print)
ISSN 1846-7989 (Online)
Volume 38
Issue 2
eng
info:eu-repo/semantics/openAccess
oai:hrcak.srce.hr:1322
2008-06-03
journal:27
Periodic solutions of a first order differential equation
Čaklović, Lavoslav
Differential equations; periodic solution; degree; Hamiltonian system
The first order dynamical system z' = F(t,z) is considered, where F is T-periodic in time and sub-linear at infinity. Existence of T-periodic solution is proved, using degree theory, and applications to non-convex Hamiltonian systems is given as well.
Croatian Mathematical Society and Department of Mathematics, University of Zagreb
2003
text
info:eu-repo/semantics/article
info:eu-repo/semantics/publishedVersion
application/pdf
https://hrcak.srce.hr/1322
https://hrcak.srce.hr/file/2292
Glasnik matematički
ISSN 0017-095X (Print)
ISSN 1846-7989 (Online)
Volume 38
Issue 2
eng
info:eu-repo/semantics/openAccess
oai:hrcak.srce.hr:1323
2008-06-03
journal:27
A discrete boundary value problem with parameters in Banach space
Kubiaczyk, I.
Morchalo, J.
Puk, A.
Difference equations; boundary value problems; Banach space
In the present note we are concerned with the question of the existence and uniqueness of solutions of two-point boundary value problem for nonlinear difference equations with parameters in Banach space.The proof of the above problem is based on the method of successive approximation and fixed-point method.
Croatian Mathematical Society and Department of Mathematics, University of Zagreb
2003
text
info:eu-repo/semantics/article
info:eu-repo/semantics/publishedVersion
application/pdf
https://hrcak.srce.hr/1323
https://hrcak.srce.hr/file/2293
Glasnik matematički
ISSN 0017-095X (Print)
ISSN 1846-7989 (Online)
Volume 38
Issue 2
eng
info:eu-repo/semantics/openAccess
oai:hrcak.srce.hr:1324
2008-06-03
journal:27
Projection-invariants, Gram-Schmidt operators, and wavelets
Pemba, Jean-Paul
Quasiorthonormality; Gram-Schmidt operator; frame; wavelet
We introduce some projection-invariants for a normalized sequence in a Hilbert space, based on the smallness of the mutual projections of its elements. We then establish conditions to have the original sequence equivalent to its Gram-Schmidt orthonormalization. In many problems of wavelet-decomposition and reconstruction, the use of orthogonal bases cannot be implemented in the construction of certain filters and other practical features. Then, a quasiorthonormal structure for representation may be the next best alternative by achieving new constraints while we can still arbitrarily approximate the powerful classical orthogonal results.
Croatian Mathematical Society and Department of Mathematics, University of Zagreb
2003
text
info:eu-repo/semantics/article
info:eu-repo/semantics/publishedVersion
application/pdf
https://hrcak.srce.hr/1324
https://hrcak.srce.hr/file/2294
Glasnik matematički
ISSN 0017-095X (Print)
ISSN 1846-7989 (Online)
Volume 38
Issue 2
eng
info:eu-repo/semantics/openAccess
oai:hrcak.srce.hr:1325
2008-06-03
journal:27
Banach-Steinhaus theorems for bounded linear operators with values in a generalized 2-normed space
Lewandowska, Zofia
2-normed space; Banach-Steinhaus theorems; 2-norm in the space of linear operators
In this paper we will prove Banach-Steinhaus theorems for some families of bounded linear operators from a normed space into a generalized 2-normed space.
Croatian Mathematical Society and Department of Mathematics, University of Zagreb
2003
text
info:eu-repo/semantics/article
info:eu-repo/semantics/publishedVersion
application/pdf
https://hrcak.srce.hr/1325
https://hrcak.srce.hr/file/2295
Glasnik matematički
ISSN 0017-095X (Print)
ISSN 1846-7989 (Online)
Volume 38
Issue 2
eng
info:eu-repo/semantics/openAccess
oai:hrcak.srce.hr:1326
2008-06-03
journal:27
Extensions of Hilbert C*-modules II
Bakić, Damir
Guljaš, Boris
Hilbert C*-module; adjointable operator; extension; multiplier algebra
We describe the pullback construction in the category of Hilbert C*-modules (with a suitable class of morphisms) in terms of pullbacks of underlying C*-algebras. In the second section the Busby invariant for extensions of Hilbert C*-modules is introduced and it is proved that each extension is uniquely determined, up to isomorphism, by the corresponding Busby map. The induced extensions of the underlying C*-algebras as well as of the corresponding linking algebras are also discussed. The paper ends with a Hilbert C*-module version of a familiar result which states that a C*-algebra is projective if and only if it is corona projective.
Croatian Mathematical Society and Department of Mathematics, University of Zagreb
2003
text
info:eu-repo/semantics/article
info:eu-repo/semantics/publishedVersion
application/pdf
https://hrcak.srce.hr/1326
https://hrcak.srce.hr/file/2296
Glasnik matematički
ISSN 0017-095X (Print)
ISSN 1846-7989 (Online)
Volume 38
Issue 2
eng
info:eu-repo/semantics/openAccess
oai:hrcak.srce.hr:1327
2008-06-03
journal:27
The expectation of solution of random continuity equation with Gaussian velocity field
Pasarić, Zoran
Random transport equation
The continuity equation in d-dimensional space with random velocity field defined by means of a vector-valued Gaussian process is studied. The expectation of corresponding evolution family of operators is explicitly derived, generalizing in a sense the evolution family corresponding to the conventional diffusion equation.
Croatian Mathematical Society and Department of Mathematics, University of Zagreb
2003
text
info:eu-repo/semantics/article
info:eu-repo/semantics/publishedVersion
application/pdf
https://hrcak.srce.hr/1327
https://hrcak.srce.hr/file/2297
Glasnik matematički
ISSN 0017-095X (Print)
ISSN 1846-7989 (Online)
Volume 38
Issue 2
eng
info:eu-repo/semantics/openAccess
oai:hrcak.srce.hr:1328
2008-06-03
journal:27
Approximate resolutions and the fractal category
Miyata, Takahisa
Watanabe, Tadashi
Approximate resolution; surjective map; box-counting dimension; category
This paper concerns the theory of approximate resolutions and its application to fractal geometry. In this paper, we first characterize a surjective map f : X Y between compact metric spaces in terms of a property on any approximate map f : X Y where p : X X and q : Y Y are any choices of approximate resolutions of X and Y, respectively. Using this characterization, we construct a category whose objects are approximate sequences so that the box-counting dimension, which was defined for approximate resolutions by the authors, is invariant in this category. To define the morphisms of the category, we introduce an equivalence relation on approximate maps and define the morphisms as the equivalence classes.
Croatian Mathematical Society and Department of Mathematics, University of Zagreb
2003
text
info:eu-repo/semantics/article
info:eu-repo/semantics/publishedVersion
application/pdf
https://hrcak.srce.hr/1328
https://hrcak.srce.hr/file/2298
Glasnik matematički
ISSN 0017-095X (Print)
ISSN 1846-7989 (Online)
Volume 38
Issue 2
eng
info:eu-repo/semantics/openAccess
oai:hrcak.srce.hr:1329
2008-06-03
journal:27
A fan X admits a Whitney map for C(X) iff it is metrizable
Lončar, Ivan
Fan; hyperspace; inverse system; Whitney map
Let X be a non-metric continuum, and C(X) be the hyperspace of subcontinua of X. It is known that there is no Whitney map on the hyperspace 2X for non-metrizable Hausdorff compact spaces X. On the other hand, there exist non-metrizable continua which admit and ones which do not admit a Whitney map for C(X). In this paper we will show that a generalized fan X admits a Whitney map for C(X) if and only if it is metrizable.
Croatian Mathematical Society and Department of Mathematics, University of Zagreb
2003
text
info:eu-repo/semantics/article
info:eu-repo/semantics/publishedVersion
application/pdf
https://hrcak.srce.hr/1329
https://hrcak.srce.hr/file/2299
Glasnik matematički
ISSN 0017-095X (Print)
ISSN 1846-7989 (Online)
Volume 38
Issue 2
eng
info:eu-repo/semantics/openAccess
oai:hrcak.srce.hr:1330
2008-06-03
journal:27
Some symmetric (47,23,11) designs
Crnković, Dean
Rukavina, Sanja
Symmetric design; Hadamard design; orbit structure; automorphism group; Mathieu group
Up to isomorphism there are precisely fifty-four symmetric designs with parameters (47,23,11) admitting a faithful action of a Frobenius group of order 55. From these fifty-four designs one can construct 179 pairwise nonisomorphic 2-(23,11,10) designs as derived and 191 pairwise nonisomorphic 2-(24,12,11) designs as residual designs. We have determined full automorphism groups of all constructed designs. One of 2-(24,12,11) designs has full automorphism group of order 15840, isomorphic to the group M11 × 2, acting transitively on the set of points.
Croatian Mathematical Society and Department of Mathematics, University of Zagreb
2003
text
info:eu-repo/semantics/article
info:eu-repo/semantics/publishedVersion
application/pdf
https://hrcak.srce.hr/1330
https://hrcak.srce.hr/file/2300
Glasnik matematički
ISSN 0017-095X (Print)
ISSN 1846-7989 (Online)
Volume 38
Issue 1
eng
info:eu-repo/semantics/openAccess
oai:hrcak.srce.hr:1331
2008-06-03
journal:27
Near squares in linear recurrence sequences
Walsh, P. G.
Linear recurrence sequence; diophantine equation; Pell equation
Let T > 1 denote a positive integer. Let Un denote the linear recurrence sequence defined by U0 = 0, U1 = 1, and Uk+1 = 2TUk - Uk-1 for k 1. In recent years there have been some improvements on the determination of solutions to the Diophantine equation Un = cx2, where c is a given positive integer. In this paper we use a result of Bennett and the author to determine precisely the integer solutions to the related equation Un = cx2 1, where c is a given even positive integer.
Croatian Mathematical Society and Department of Mathematics, University of Zagreb
2003
text
info:eu-repo/semantics/article
info:eu-repo/semantics/publishedVersion
application/pdf
https://hrcak.srce.hr/1331
https://hrcak.srce.hr/file/2301
Glasnik matematički
ISSN 0017-095X (Print)
ISSN 1846-7989 (Online)
Volume 38
Issue 1
eng
info:eu-repo/semantics/openAccess
oai:hrcak.srce.hr:1332
2008-06-03
journal:27
On stability of critical points of quadratic differential equations in nonassociative algebras
Zalar, Borut
Mencinger, Matej
Quadratic differential equation; nonassociative algebra; critical points; ray solutions; projections; nilpotents; Peirce subspaces
In this note we treat the stability of nonzero critical points of the differential equation x' = x2 in a commutative real nonassociative algebra. As our first result we prove that if a critical point lies in some Peirce subspace with respect to a nonzero idempotent, it cannot be stable. This improves a previously known result due to Kinyon and Sagle. As a second result we show that there exists 2-dimensional algebra
Croatian Mathematical Society and Department of Mathematics, University of Zagreb
2003
text
info:eu-repo/semantics/article
info:eu-repo/semantics/publishedVersion
application/pdf
https://hrcak.srce.hr/1332
https://hrcak.srce.hr/file/2302
Glasnik matematički
ISSN 0017-095X (Print)
ISSN 1846-7989 (Online)
Volume 38
Issue 1
eng
info:eu-repo/semantics/openAccess
oai:hrcak.srce.hr:1333
2008-06-03
journal:27
On a generalization of the sine function
Szostok, Tomasz
Birkhoff-James orthogonality; functional equation; inner product space
A function
s(x,y) = inf { ||x + y|| / ||x|| : }
strictly connected with Birkhoff-James orthogonality is considered. This function may be used in functional equations theory, to provide unconditional equations in place of orthogonal equations in the sense of Birkhoff-James. Moreover, we deal with another generalization of the sine function which, in particular leads to a characterization of inner product spaces.
Croatian Mathematical Society and Department of Mathematics, University of Zagreb
2003
text
info:eu-repo/semantics/article
info:eu-repo/semantics/publishedVersion
application/pdf
https://hrcak.srce.hr/1333
https://hrcak.srce.hr/file/2303
Glasnik matematički
ISSN 0017-095X (Print)
ISSN 1846-7989 (Online)
Volume 38
Issue 1
eng
info:eu-repo/semantics/openAccess
oai:hrcak.srce.hr:1334
2008-06-03
journal:27
Local stability of the additive functional equation
Jung, Soon-Mo
Hyers-Ulam stability; local stability; additive functional equation; Jensen's functional equation
In this paper, we prove the Hyers-Ulam stability of the additive functional equation for a number of unbounded domains. We moreover prove the stability of Jensen's functional equation for a large class of restricted domains.
Croatian Mathematical Society and Department of Mathematics, University of Zagreb
2003
text
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https://hrcak.srce.hr/1334
https://hrcak.srce.hr/file/2304
Glasnik matematički
ISSN 0017-095X (Print)
ISSN 1846-7989 (Online)
Volume 38
Issue 1
eng
info:eu-repo/semantics/openAccess
oai:hrcak.srce.hr:1335
2008-06-03
journal:27
On absolute normal double matrix summability methods
Rhoades, B. E.
Absolute summability; weighted mean matrix; Cesaro matrix; inclusion theorems
It is shown that, if T is a row finite nonnegative double summability matrix satisfying certain conditions, then |T|k summability is stronger than |N, pn|k summability, for k 1. As special summability methods T we consider weighted mean and double Cesaro, (C, 1, 1), methods.
Croatian Mathematical Society and Department of Mathematics, University of Zagreb
2003
text
info:eu-repo/semantics/article
info:eu-repo/semantics/publishedVersion
application/pdf
https://hrcak.srce.hr/1335
https://hrcak.srce.hr/file/2305
Glasnik matematički
ISSN 0017-095X (Print)
ISSN 1846-7989 (Online)
Volume 38
Issue 1
eng
info:eu-repo/semantics/openAccess
oai:hrcak.srce.hr:1336
2008-06-03
journal:27
Connectivity in the set of Tight Frame Wavelets (TFW)
Garrigos, Gustavo
Hernandez, Eugenio
Šikić, Hrvoje
Soria, Fernando
Weiss, Guido
Wilson, Edward
Connectivity; tight frames; wavelets
We introduce new ideas to treat the problem of connectivity of wavelets. We develop a method which produces intermediate paths of Tight Frame Wavelets (TFW). Using this method we prove that a large class of TFW-s, with only mild conditions on their spectrum, are arcwise connected.
Croatian Mathematical Society and Department of Mathematics, University of Zagreb
2003
text
info:eu-repo/semantics/article
info:eu-repo/semantics/publishedVersion
application/pdf
https://hrcak.srce.hr/1336
https://hrcak.srce.hr/file/2306
Glasnik matematički
ISSN 0017-095X (Print)
ISSN 1846-7989 (Online)
Volume 38
Issue 1
eng
info:eu-repo/semantics/openAccess
oai:hrcak.srce.hr:1337
2008-06-03
journal:27
On 2-normed sets
Lewandowska, Zofia
2-normed set; 2-normed space; 2-norm in the space of linear operators
In this paper we consider properties of the 2-normed sets and we construct two 2-normed sets of linear operators.
Croatian Mathematical Society and Department of Mathematics, University of Zagreb
2003
text
info:eu-repo/semantics/article
info:eu-repo/semantics/publishedVersion
application/pdf
https://hrcak.srce.hr/1337
https://hrcak.srce.hr/file/2307
Glasnik matematički
ISSN 0017-095X (Print)
ISSN 1846-7989 (Online)
Volume 38
Issue 1
eng
info:eu-repo/semantics/openAccess
oai:hrcak.srce.hr:1338
2008-06-03
journal:27
A note on quasi-isometries II
Patel, S. M.
Hilbert space; isometry; spectrum; operator matrix
An operator A on a complex Hilbert space H is called a quasi-isometry if A*2 A2 = A* A. In the present article, some structural properties of quasi-isometries are established with the help of operator matrix representation.
Croatian Mathematical Society and Department of Mathematics, University of Zagreb
2003
text
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info:eu-repo/semantics/publishedVersion
application/pdf
https://hrcak.srce.hr/1338
https://hrcak.srce.hr/file/2308
Glasnik matematički
ISSN 0017-095X (Print)
ISSN 1846-7989 (Online)
Volume 38
Issue 1
eng
info:eu-repo/semantics/openAccess
oai:hrcak.srce.hr:1339
2008-06-03
journal:27
The extension dimension of universal spaces
Ivanšić, Ivan
Rubin, Leonard R.
Extension theory; extension dimension; dimension; stratifiable space; subspace theorem
Let be an infinite cardinal, denote a class of CW-complexes, the class of all compact Hausdorff spaces, the class of all metrizable spaces of weight and n 0. We shall prove that,
(a) if U is a universal metrizable space of covering dimension n and weight , then ext-dim_(, ) U = [Sn], and
(b) if U , K , dim U K, and U contains a copy of every compact metrizable space X with dim X K, then ext-dim_(, ) U = [K].
Croatian Mathematical Society and Department of Mathematics, University of Zagreb
2003
text
info:eu-repo/semantics/article
info:eu-repo/semantics/publishedVersion
application/pdf
https://hrcak.srce.hr/1339
https://hrcak.srce.hr/file/2309
Glasnik matematički
ISSN 0017-095X (Print)
ISSN 1846-7989 (Online)
Volume 38
Issue 1
eng
info:eu-repo/semantics/openAccess
oai:hrcak.srce.hr:1340
2008-06-03
journal:27
Bi-Lipschitz maps and the category of approximate resolutions
Miyata, Takahisa
Watanabe, Tadashi
Approximate resolution; biLipschitz map; Lipschitz map; box-counting dimension; category
In this paper we consider biLipschitz maps between compact spaces with the metrics which are induced by given approximate resolutions. More precisely, we characterize biLipschitz maps in terms of conditions on any approximate resolutions of the maps. We then show that the box-counting dimension for approximate resolutions which was introduced earlier is invariant under approximate maps corresponding to biLipschitz maps. Moreover, we construct categories whose objects are approximate resolutions and in which the box-counting dimension is invariant.
Croatian Mathematical Society and Department of Mathematics, University of Zagreb
2003
text
info:eu-repo/semantics/article
info:eu-repo/semantics/publishedVersion
application/pdf
https://hrcak.srce.hr/1340
https://hrcak.srce.hr/file/2310
Glasnik matematički
ISSN 0017-095X (Print)
ISSN 1846-7989 (Online)
Volume 38
Issue 1
eng
info:eu-repo/semantics/openAccess
oai:hrcak.srce.hr:1341
2008-06-03
journal:27
Fuzzy P-spaces games and metacompactness
John, Sunil Jacob
Fuzzy topological spaces; fuzzy topological games; Pα-spaces; shading families
Fuzzy P-spaces are introduced and a characterization for the same in terms of a particular type of fuzzy topological game is obtained. Further some applications of fuzzy P-spaces in product -metacompact spaces are also investigated.
Croatian Mathematical Society and Department of Mathematics, University of Zagreb
2003
text
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info:eu-repo/semantics/publishedVersion
application/pdf
https://hrcak.srce.hr/1341
https://hrcak.srce.hr/file/2311
Glasnik matematički
ISSN 0017-095X (Print)
ISSN 1846-7989 (Online)
Volume 38
Issue 1
eng
info:eu-repo/semantics/openAccess
oai:hrcak.srce.hr:1342
2008-06-03
journal:27
Dendroids and preorders
Neumann-Lara, Victor
Puga, Isabel
Wilson, Richard G.
Dendroid; preordered set; partially ordered set
Let X be a dendroid and x* X. 0(X, x*) will denote the preordered set of arc-components of X {x*}, where the preorder is defined by if cl(). In this paper we investigate conditions under which there exists a pair (X,x*) such that 0(X, x*) is isomorphic to a given preordered set.
Croatian Mathematical Society and Department of Mathematics, University of Zagreb
2003
text
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application/pdf
https://hrcak.srce.hr/1342
https://hrcak.srce.hr/file/2312
Glasnik matematički
ISSN 0017-095X (Print)
ISSN 1846-7989 (Online)
Volume 38
Issue 1
eng
info:eu-repo/semantics/openAccess
oai:hrcak.srce.hr:1343
2008-06-03
journal:27
Movable categories
Gevorgyan, P. S.
Shape theory; movability; category
The notion of movability for metrizable compacta was introduced by K.Borsuk. In this paper we define the notion of a movable category and prove that the movability of a topological space X coincides with the movability of a suitable category, which is generated by the topological space X (i.e., the category X, defined by S.Mardesic).
Croatian Mathematical Society and Department of Mathematics, University of Zagreb
2003
text
info:eu-repo/semantics/article
info:eu-repo/semantics/publishedVersion
application/pdf
https://hrcak.srce.hr/1343
https://hrcak.srce.hr/file/2313
Glasnik matematički
ISSN 0017-095X (Print)
ISSN 1846-7989 (Online)
Volume 38
Issue 1
eng
info:eu-repo/semantics/openAccess
oai:hrcak.srce.hr:1344
2008-06-03
journal:27
A uniformly accurate finite elements method for singular perturbation problems
Stojanović, Mirjana
Petrov Galerkin method of finite elements; singularly perturbed problem; uniform convergence
We consider piecewise polynomial finite elements method for a singular perturbation problem. The finite elements method of Griffiths for a problem with non-constant coefficients was adapted by introducing piecewise polynomial approximation. We generate the tridiagonal difference schemes which are second order accurate in uniform norm.
Croatian Mathematical Society and Department of Mathematics, University of Zagreb
2003
text
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application/pdf
https://hrcak.srce.hr/1344
https://hrcak.srce.hr/file/2314
Glasnik matematički
ISSN 0017-095X (Print)
ISSN 1846-7989 (Online)
Volume 38
Issue 1
eng
info:eu-repo/semantics/openAccess
oai:hrcak.srce.hr:3294
2008-06-03
journal:27
Computational experiences on norm form equations with solutions forming arithmetic progressions
Bérczes, Attila
Pethö, Attila
Norm form equation; arithmetic progression; binomial Thue equation
In the present paper we solve the equation
NK/Q(x0 + x1α + x2α2 + ... + xn -1αn -1) = 1
in x0, ... , xn -1 ∈ Z, such that x0, ... , xn -1 is an arithmetic progression, where α is a root of the polynomial xn - a, for all integers 2 ≤ a ≤ 100 and n ≥ 3.
Croatian Mathematical Society and Department of Mathematics, University of Zagreb
2006
text
info:eu-repo/semantics/article
info:eu-repo/semantics/publishedVersion
application/pdf
https://hrcak.srce.hr/3294
https://hrcak.srce.hr/file/5546
Glasnik matematički
ISSN 0017-095X (Print)
ISSN 1846-7989 (Online)
Volume 41
Issue 1
eng
info:eu-repo/semantics/openAccess
oai:hrcak.srce.hr:3295
2008-06-03
journal:27
On a certain family of quartic Thue equations with three parameters
Ziegler, Volker
Diophantine equations; parameterized Thue equations; norm form equations; simultaneous Pellian equations
We consider the parameterized Thue equation
X4 - 4sX3Y - (2ab + 4(a + b)s)X2Y2 - 4absXY3 + a2b2Y4 = ± 1,
with a, b ∈ 1/4 Z such that ab ∈ Z. By the hypergeometric method and a method of Tzanakis we find all solutions, if s is large with respect to |a| and |b|.
Croatian Mathematical Society and Department of Mathematics, University of Zagreb
2006
text
info:eu-repo/semantics/article
info:eu-repo/semantics/publishedVersion
application/pdf
https://hrcak.srce.hr/3295
https://hrcak.srce.hr/file/5547
Glasnik matematički
ISSN 0017-095X (Print)
ISSN 1846-7989 (Online)
Volume 41
Issue 1
eng
info:eu-repo/semantics/openAccess
oai:hrcak.srce.hr:3296
2008-06-03
journal:27
2-rang du groupe des classes et courbes elliptiques
Laoudi, Aïni
Dans cet article, nous étudions la relation qui existe entre le 2-rang du groupe des classes d'une famille de corps cubiques et le rang d'une famille de courbes elliptiques.
Croatian Mathematical Society and Department of Mathematics, University of Zagreb
2006
text
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info:eu-repo/semantics/publishedVersion
application/pdf
https://hrcak.srce.hr/3296
https://hrcak.srce.hr/file/5549
Glasnik matematički
ISSN 0017-095X (Print)
ISSN 1846-7989 (Online)
Volume 41
Issue 1
fre
info:eu-repo/semantics/openAccess
oai:hrcak.srce.hr:3297
2008-06-03
journal:27
On functional equations related to bicircular projections
Vukman, Joso
*-ring; semiprime ring; derivation; left (right) centralizer; bicircular projection
In this paper we prove the following result. Let R be a 2-torsion free semiprime *-ring. Suppose that D, G : R → R are additive mappings satisfying the relations
D(xyx) = D(x)yx + xG(y*)*x + xyD(x), G(xyx) = G(x)yx + xD(y*)*x + xyG(x),
for all pairs x, y ∈ R. In this case D and G are of the form
8D(x) = 2(d(x) + g(x)) + (p + q)x + x(p + q), 8G(x) = 2(d(x) - g(x)) + (q - p)x + x(q - p),
for all x ∈ R, where d, g are derivations of R and p, q are some elements from symmetric Martindale ring of quotients of R. Besides, d(x) = -d(x*)*, g(x) = g(x*)*, for all x ∈ R, and p* = p, q* = -q.
Croatian Mathematical Society and Department of Mathematics, University of Zagreb
2006
text
info:eu-repo/semantics/article
info:eu-repo/semantics/publishedVersion
application/pdf
https://hrcak.srce.hr/3297
https://hrcak.srce.hr/file/5550
Glasnik matematički
ISSN 0017-095X (Print)
ISSN 1846-7989 (Online)
Volume 41
Issue 1
eng
info:eu-repo/semantics/openAccess
oai:hrcak.srce.hr:3298
2008-06-03
journal:27
On commutativity of σ-prime rings
Oukhtite, L.
Salhi, S.
Rings with involution; σ-prime rings; centralizing automorphisms; square closed Lie ideals; derivations; commutativity
Let R be a 2-torsion free σ-prime ring having a σ-square closed Lie ideal U and an automorphism T centralizing on U. We prove that if there exists u0 in Saσ(R) with Ru0 ⊂ U and if T commutes with σ on U, then U is contained in the center of R. This result is then applied to generalize the result of J. Mayne for centralizing automorphisms to σ-prime rings. Finally, for a 2-torsion free σ-prime ring possessing a nonzero derivation, we give suitable conditions under which the ring must be commutative.
Croatian Mathematical Society and Department of Mathematics, University of Zagreb
2006
text
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application/pdf
https://hrcak.srce.hr/3298
https://hrcak.srce.hr/file/5551
Glasnik matematički
ISSN 0017-095X (Print)
ISSN 1846-7989 (Online)
Volume 41
Issue 1
eng
info:eu-repo/semantics/openAccess
oai:hrcak.srce.hr:3299
2008-06-03
journal:27
A class of nonabelian nonmetacyclic finite 2-groups
Ćepulić, Vladimir
Pyliavska, Olga S.
Finite group; 2-group; abelian; metacyclic
Nonabelian nonmetacyclic finite 2-groups in which every proper subgroup is abelian or metacyclic and possessing at least one nonabelian and at least one nonmetacyclic proper subgroup have been investigated and classified. Using the obtained result and two previously known results one gets the complete classification of all nonabelian nonmetacyclic finite 2-groups in which every proper subgroup is abelian or metacyclic.
Croatian Mathematical Society and Department of Mathematics, University of Zagreb
2006
text
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info:eu-repo/semantics/publishedVersion
application/pdf
https://hrcak.srce.hr/3299
https://hrcak.srce.hr/file/5552
Glasnik matematički
ISSN 0017-095X (Print)
ISSN 1846-7989 (Online)
Volume 41
Issue 1
eng
info:eu-repo/semantics/openAccess
oai:hrcak.srce.hr:3300
2008-06-03
journal:27
Finite 2-groups G with Ω2*(G) metacyclic
Janko, Zvonimir
Finite 2-groups; 2-groups of maximal class; metacyclic groups
In this paper we classify finite non-metacyclic 2-groups G such that Ω2*(G) (the subgroup generated by all elements of order 4) is metacyclic. However, if G is a finite 2-group such that Ω2(G) (the subgroup generated by all elements of order ≤ 4) is metacyclic, then G is metacyclic.
Croatian Mathematical Society and Department of Mathematics, University of Zagreb
2006
text
info:eu-repo/semantics/article
info:eu-repo/semantics/publishedVersion
application/pdf
https://hrcak.srce.hr/3300
https://hrcak.srce.hr/file/5553
Glasnik matematički
ISSN 0017-095X (Print)
ISSN 1846-7989 (Online)
Volume 41
Issue 1
eng
info:eu-repo/semantics/openAccess
oai:hrcak.srce.hr:3301
2008-06-03
journal:27
A note on reduction of dimension for linear elliptic equations
Aganović, Ibrahim
Tambača, Josip
Tutek, Zvonimir
Reduction dimension; elliptic equation; formal expansion method; Ansatz
In this paper we consider the linear elliptic equation of the second order in domains in Rn thin in n - k directions, 0 < k < n. We apply the Ansatz of the formal expansion method (with respect to the small parameter (thickness)) which implies the scaling of the loads in the equation that allows the reduction of the problem from dimension n to dimension k. Appropriate convergence result together with correctors is derived.
Croatian Mathematical Society and Department of Mathematics, University of Zagreb
2006
text
info:eu-repo/semantics/article
info:eu-repo/semantics/publishedVersion
application/pdf
https://hrcak.srce.hr/3301
https://hrcak.srce.hr/file/5554
Glasnik matematički
ISSN 0017-095X (Print)
ISSN 1846-7989 (Online)
Volume 41
Issue 1
eng
info:eu-repo/semantics/openAccess
oai:hrcak.srce.hr:3302
2008-06-03
journal:27
A note on calculation of asymptotic energy for Ginzburg-Landau functional with ε-dependent 1-Lipschitz penalizing term in one dimension
Raguž, Andrija
Young measures; relaxation; Ginzburg-Landau functional; Gamma convergence
We study asymptotic behavior of the Ginzburg-Landau functional
as ε → 0, where (gε) is a given sequence of 1-Lipschitz functions. In cases where the sequence (gε) possesses some additional properties we calculate (rescaled) minimal macroscopic energy associated to Iεgε as ε → 0. Thus we obtain partial generalization of our previous results.
Croatian Mathematical Society and Department of Mathematics, University of Zagreb
2006
text
info:eu-repo/semantics/article
info:eu-repo/semantics/publishedVersion
application/pdf
https://hrcak.srce.hr/3302
https://hrcak.srce.hr/file/5555
Glasnik matematički
ISSN 0017-095X (Print)
ISSN 1846-7989 (Online)
Volume 41
Issue 1
eng
info:eu-repo/semantics/openAccess
oai:hrcak.srce.hr:3303
2008-06-03
journal:27
Homogenization of random degenerated nonlinear monotone operators
Engström, J.
Persson, L.-E.
Piatnitski, A.
Wall, P.
Stochastic homogenization; random operators; degenerated monotone operators
This paper deals with homogenization of random nonlinear monotone operators in divergence form. We assume that the structure conditions (strict monotonicity and continuity conditions) degenerate and are given in terms of a weight function. Under proper integrability assumptions on the weight function we construct the effective operator and prove the homogenization result.
Croatian Mathematical Society and Department of Mathematics, University of Zagreb
2006
text
info:eu-repo/semantics/article
info:eu-repo/semantics/publishedVersion
application/pdf
https://hrcak.srce.hr/3303
https://hrcak.srce.hr/file/5556
Glasnik matematički
ISSN 0017-095X (Print)
ISSN 1846-7989 (Online)
Volume 41
Issue 1
eng
info:eu-repo/semantics/openAccess
1603675120033