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On linear operators and functors extending pseudometrics

C. Bessaga (1993)

Fundamenta Mathematicae

For some pairs (X,A), where X is a metrizable topological space and A its closed subset, continuous, linear (i.e., additive and positive-homogeneous) operators extending metrics for A to metrics for X are constructed. They are defined by explicit analytic formulas, and also regarded as functors between certain categories. An essential role is played by "squeezed cones" related to the classical cone construction. The main result: if A is a nondegenerate absolute neighborhood retract for metric spaces,...

On shape

Ralph Fox (1972)

Fundamenta Mathematicae

On the disjoint (0,N)-cells property for homogeneous ANR's

Paweł Krupski (1993)

Colloquium Mathematicae

A metric space (X,ϱ) satisfies the disjoint (0,n)-cells property provided for each point x ∈ X, any map f of the n-cell B n into X and for each ε > 0 there exist a point y ∈ X and a map g : B n X such that ϱ(x,y) < ε, ϱ ^ ( f , g ) < ε and y g ( B n ) . It is proved that each homogeneous locally compact ANR of dimension >2 has the disjoint (0,2)-cells property. If dimX = n > 0, X has the disjoint (0,n-1)-cells property and X is a locally compact L C n - 1 -space then local homologies satisfy H k ( X , X - x ) = 0 for k < n and Hn(X,X-x) ≠ 0.

On the structure of fixed point sets of some compact maps in the Fréchet space

Zbyněk Kubáček (1993)

Mathematica Bohemica

The aim of this note is 1. to show that some results (concerning the structure of the solution set of equations (18) and (21)) obtained by Czarnowski and Pruszko in [6] can be proved in a rather different way making use of a simle generalization of a theorem proved by Vidossich in [8]; and 2. to use a slight modification of the “main theorem” of Aronszajn from [1] applying methods analogous to the above mentioned idea of Vidossich to prove the fact that the solution set of the equation (24), (25)...

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