Original scientific paper

https://doi.org/10.3336/gm.42.1.06

Local characterization of absolute co-extensors

Ivan Ivanšić ; Department of Mathematics, University of Zagreb, Unska 3, P.O. Box 148, 10001 Zagreb, Croatia
Leonard R. Rubin orcid.org/0000-0002-1108-0267 ; Department of Mathematics, University of Oklahoma, Norman, Oklahoma 73019, USA

Abstract

Suppose that K is a space and X is a paracompact space. We show that X is an absolute co-extensor for K (i.e., K is an absolute extensor for X) if and only if it is a local absolute co-extensor for K. We also provide a similar characterization using a weaker local extension property. The property that X is an absolute co-extensor for K is inherited by closed subsets but not necessarily by open subsets of X. We also present several extension results for open subsets of stratifiable spaces if K is a CW-complex.

Keywords

Absolute co-extensor; absolute extensor; paracompact space; stratifiable space; local property

Hrčak ID:

12883

URI

https://hrcak.srce.hr/12883

Publication date:

12.6.2007.

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