Absolutely minimizing Lipschitz extensions on a metric space.
Absolutely strongly star-Hurewicz spaces
A space X is absolutely strongly star-Hurewicz if for each sequence (Un :n ∈ℕ/ of open covers of X and each dense subset D of X, there exists a sequence (Fn :n ∈ℕ/ of finite subsets of D such that for each x ∈X, x ∈St(Fn; Un) for all but finitely many n. In this paper, we investigate the relationships between absolutely strongly star-Hurewicz spaces and related spaces, and also study topological properties of absolutely strongly star-Hurewicz spaces.
Absolutely terminal continua and confluent mappings
Interrelations between three concepts of terminal continua and their behaviour, when the underlying continuum is confluently mapped, are studied.
Abstract Characterizations of Continuous Functions.
Abstract Characterizations of Continuous Functions. (Short Communication).
AC holds iff every compact completely regular topology can be extended to a compact Tychonoff topology
We show that AC is equivalent to the assertion that every compact completely regular topology can be extended to a compact Tychonoff topology.
Accessibility spaces, -spaces and initial topologies
Acyclic Maps and Knot Complements.
Addendum to the paper: “Some fixed point theorems for multivalued mappings”
Additive selections of superadditive set-valued functions.
Adequate families of sets and Corson compacts
Adequate families of sets and function spaces
Adjungiertenbildungen in der Operatortheorie.
Admissible maps, intersection results, coincidence theorems
We obtain generalizations of the Fan's matching theorem for an open (or closed) covering related to an admissible map. Each of these is restated as a KKM theorem. Finally, applications concerning coincidence theorems and section results are given.
Affine group acting on hyperspaces of compact convex subsets of ℝⁿ
For every n ≥ 2, let cc(ℝⁿ) denote the hyperspace of all nonempty compact convex subsets of the Euclidean space ℝⁿ endowed with the Hausdorff metric topology. Let cb(ℝⁿ) be the subset of cc(ℝⁿ) consisting of all compact convex bodies. In this paper we discover several fundamental properties of the natural action of the affine group Aff(n) on cb(ℝⁿ). We prove that the space E(n) of all n-dimensional ellipsoids is an Aff(n)-equivariant retract of cb(ℝⁿ). This is applied to show that cb(ℝⁿ) is homeomorphic...
Affine selections of convex set-valued functions.
Alcune caratterizzazioni di una sottoalgebra di e compattificazioni ad essa associate
Alcuni risultati su proprietà di ricoprimento e sulla spezzabilità
Algebraic characterization of finite (branched) coverings
Every continuous map X → S defines, by composition, a homomorphism between the corresponding algebras of real-valued continuous functions C(S) → C(X). This paper deals with algebraic properties of the homomorphism C(S) → C(X) in relation to topological properties of the map X → S. The main result of the paper states that a continuous map X → S between topological manifolds is a finite (branched) covering, i.e., an open and closed map whose fibres are finite, if and only if the induced homomorphism...
Algebraic properties of quasi-finite complexes
A countable CW complex K is quasi-finite (as defined by A. Karasev) if for every finite subcomplex M of K there is a finite subcomplex e(M) such that any map f: A → M, where A is closed in a separable metric space X satisfying XτK, has an extension g: X → e(M). Levin's results imply that none of the Eilenberg-MacLane spaces K(G,2) is quasi-finite if G ≠ 0. In this paper we discuss quasi-finiteness of all Eilenberg-MacLane spaces. More generally, we deal with CW complexes with finitely many...