The metric confluent images of half-lines and lines
The openness of induced maps on hyperspaces
The pseudo-arc as an inverse limit with simple bonding maps
The set function T and homotopies
The star compactification.
The Tamano Theorem in
In this paper we continue with the study of paracompact maps introduced in [1]. We give two external characterizations for paracompact maps including a characterization analogous to The Tamano Theorem in the category (of topological spaces and continuous maps as morphisms). A necessary and sufficient condition for the Tychonoff product of a closed map and a compact map to be closed is also given.
The topological degree and fixed points of DC-mappings
Three countable connected spaces
Topological completeness of first countable Hausdorff spaces II
Topological completeness of first countable Hausdorff spaces I
*-Topological properties.
Trivial bundles and near-homeomorphisms
True preimages of compact or separable sets for functional analysts
We discuss various results on the existence of ‘true’ preimages under continuous open maps between -spaces, -lattices and some other spaces. The aim of the paper is to provide accessible proofs of this sort of results for functional-analysts.
Two extension theorems for functions
Two theorems concerning BI-quotient maps
Two-to-one continuous images of ℕ*
A function is two-to-one if every point in the image has exactly two inverse points. We show that every two-to-one continuous image of ℕ* is homeomorphic to ℕ* when the continuum hypothesis is assumed. We also prove that there is no irreducible two-to-one continuous function whose domain is ℕ* under the same assumption.
Über offene Abbildungen auf die 3-Sphäre.
Uniform weight of uniform quotients
Uniforme Räume mit einer linear geordneten Basis.
Universal images of universal elements
We furnish several necessary and sufficient conditions for the following property: For a topological space X, a continuous selfmapping S of X and a family τ of continuous selfmappings of X, the image under S of every τ-universal element is also τ-universal. An application in operator theory, where we extend results of Bourdon, Herrero, Bes, Herzog and Lemmert, is given. In particular, it is proved that every hypercyclic operator on a real or complex Banach space has a dense invariant linear manifold...