On semi-closed sets and semi-open sets and their applications
On singlevaluedness and (strong) upper semicontinuity of maximal monotone mappings
On strongly continuous and completely continuous mappings
On Surjective Bing Maps
In [7], M. Levin proved that the set of all Bing maps of a compact metric space to the unit interval is a dense -subset of the space of all maps. In [6], J. Krasinkiewicz independently proved that the set of all Bing maps of a compact metric space to an n-dimensional manifold (n ≥ 1) is a dense -subset of the space of maps. In [9], J. Song and E. D. Tymchatyn, solving some problems of J. Krasinkiewicz ([6]), proved that the set of all Bing maps of a compact metric space to a nondegenerate connected...
On the almost monotone convergence of sequences of continuous functions
A sequence (f n)n of functions f n: X → ℝ almost decreases (increases) to a function f: X → ℝ if it pointwise converges to f and for each point x ∈ X there is a positive integer n(x) such that f n+1(x) ≤ f n (x) (f n+1(x) ≥ f n(x)) for n ≥ n(x). In this article I investigate this convergence in some families of continuous functions.
On the class of continuous images of Valdivia compacta.
On the compactification of closure algebras
On the continuity and monotonicity of restrictions of connected functions
On the continuity of functions.
On the deficiency of product spaces
On the extensions of uniformly continuous mappings
On the functionally countable subalgebra of C(X)
On the generalized property
On the product topology associated with semi-closed sets
On the relation between continuous and connected functions
On the sharpness of the ... 2 and ... 1 Nielsen numbers.
On the simplicity of some categories of closure spaces
On topological and algebraic structure of extremally disconnected semitopological groups
Starting with a very simple proof of Frol’ık’s theorem on homeomorphisms of extremally disconnected spaces, we show how this theorem implies a well known result of Malychin: that every extremally disconnected topological group contains an open and closed subgroup, consisting of elements of order . We also apply Frol’ık’s theorem to obtain some further theorems on the structure of extremally disconnected topological groups and of semitopological groups with continuous inverse. In particular, every...
On unified theory for continuities.
On universal composition of maps.
In this paper we shall introduce notions of F-universality and F-e-universality for maps between compact Hausdorff spaces and explore the behaviour of these properties under the operation of composition of maps. We consider both the quest for conditions on maps f and g which would imply that their composition g o f is either F-universal or F-e-universal and the quest for consequences on f and g when the composition g o f is either F-universal or F-e-universal. In our approach F is an arbitrary class...