The lifting property for classes of mappings.
The Lower and Upper Topologies as a Bitopology
The minimum uniform compactification of a metric space
It is shown that associated with each metric space (X,d) there is a compactification of X that can be characterized as the smallest compactification of X to which each bounded uniformly continuous real-valued continuous function with domain X can be extended. Other characterizations of are presented, and a detailed study of the structure of is undertaken. This culminates in a topological characterization of the outgrowth , where is Euclidean n-space with its usual metric.
The Möbius-Pompeiu metric property.
The Niemytzki plane is -metrizable
We prove that the Niemytzki plane is -metrizable and we try to explain the differences between the concepts of a stratifiable space and a -metrizable space. Also, we give a characterisation of -metrizable spaces which is modelled on the version described by Chigogidze.
The nonexistence of expansive homeomorphisms of chainable continua
A homeomorphism f:X → X of a compactum X with metric d is expansive if there is c > 0 such that if x, y ∈ X and x ≠ y, then there is an integer n ∈ ℤ such that . In this paper, we prove that if a homeomorphism f:X → X of a continuum X can be lifted to an onto map h:P → P of the pseudo-arc P, then f is not expansive. As a corollary, we prove that there are no expansive homeomorphisms on chainable continua. This is an affirmative answer to one of Williams’ conjectures.
The nonexistence of expansive homeomorphisms of dendroids
The number of metrizable spaces
The positive cone of a Banach lattice. Coincidence of topologies and metrizability
Let be a Banach lattice, and denote by its positive cone. The weak topology on is metrizable if and only if it coincides with the strong topology if and only if is Banach-lattice isomorphic to for a set . The weak topology on is metrizable if and only if is Banach-lattice isomorphic to a -space, where is a metrizable compact space.
The quasimetrization problem in the (bi)topological spaces.
The regularity series of a Cauchy space.
The shape theory for uniform spaces and the shape uniform invariants
The solenoids are the only circle-like continua that admit expansive homeomorphisms
A homeomorphism h:X → X of a compactum X is expansive provided that for some fixed c > 0 and any distinct x, y ∈ X there exists an integer n, dependent only on x and y, such that d(hⁿ(x),hⁿ(y)) > c. It is shown that if X is a circle-like continuum that admits an expansive homeomorphism, then X is homeomorphic to a solenoid.
The spaces of ordered lo-proximity
The structure of compacta satisfying dim(X×X) < 2dimX
The sup = max problem for the extent of generalized metric spaces
It looks not useful to study the sup = max problem for extent, because there are simple examples refuting the condition. On the other hand, the sup = max problem for Lindelöf degree does not occur at a glance, because Lindelöf degree is usually defined by not supremum but minimum. Nevertheless, in this paper, we discuss the sup = max problem for the extent of generalized metric spaces by combining the sup = max problem for the Lindelöf degree of these spaces.
The topological structure of adherences of regular languages
The undecidability of the existence of a non-separable normal Moore space satisfying the countable chain condition
The universal separable metric space of Urysohn and isometric embeddings thereof in Вanach spaces
This paper is an investigation of the universal separable metric space up to isometry U discovered by Urysohn. A concrete construction of U as a metric subspace of the space C[0,1] of functions from [0,1] to the reals with the supremum metric is given. An answer is given to a question of Sierpiński on isometric embeddings of U in C[0,1]. It is shown that the closed linear span of an isometric copy of U in a Banach space which contains the zero of the Banach space is determined up to linear isometry....
The -completion of a lattice ordered group