Inverse sequences and absolute co-extensors

• Autorzy: Ivanšic I. , Rubin R.
• Języki publikacji: EN

Abstrakty

EN

Suppose that K is a CW-complex, X is an inverse sequence of stratifiable spaces, and X = lim X. Using the concept of semi-sequence, we provide a necessary and sufficient condition for X to be an absolute co-extensor for K in terms of the inverse sequence X and without recourse to any specific properties of its limit. To say that X is an absolute co-extensor for K is the same as saying that K is an absolute extensor for X, i.e., that each map ƒ : A → K from a closed subset A of X extends to a map F : X → K. Incase K is & polyhedron |/C|cw (the set \K\ with the weak topology CW), we determine a similar characterization that takes into account the simplicial structure of K.

Słowa kluczowe

EN

absolute co-extensor; absolute extensor; absolute neighborhood extensor; canonical map; cohomological dimension; contiguity; CW-complex; Eilenberg-Mac Lane complex; extension theory; inverse limit; inverse sequence; K-modification; nerve; polyhedron; semi-sequence; semi-limit; simplicial complex; stratifiable space

• Wydawca: Instytut Matematyczny PAN
• Czasopismo: Bulletin of the Polish Academy of Sciences. Mathematics
• Rocznik: 2007
• Tom: Vol. 55, no 3
• Strony: 243--259
• Opis fizyczny: Bibliogr. 17 poz.

Twórcy

autor

Ivanšic I.

autor

Rubin R.

• Department of Mathematics, University of Zagreb, Unska 3 P.O. Box 148, 10001 Zagreb, Croatia,

Bibliografia

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