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On strongly preirresolute topological vector spaces

N. Rajesh, V. Vijayabharathi (2013)

Mathematica Bohemica

In the paper we obtain several characteristics of pre- T 2 of strongly preirresolute topological vector spaces and show that the extreme point of a convex subset of a strongly preirresolute topological vector space X lies on the boundary.

On structure space of Γ -semigroups

S. Chattopadhyay, S. Kar (2008)

Acta Universitatis Palackianae Olomucensis. Facultas Rerum Naturalium. Mathematica

In this paper we introduce the notion of the structure space of Γ -semigroups formed by the class of uniformly strongly prime ideals. We also study separation axioms and compactness property in this structure space.

On sub-, pseudo- and quasimaximal spaces

J. Schröder (1998)

Commentationes Mathematicae Universitatis Carolinae

The structure of sub-, pseudo- and quasimaximal spaces is investigated. A method of constructing non-trivial quasimaximal spaces is presented.

On subcompactness and countable subcompactness of metrizable spaces in ZF

Kyriakos Keremedis (2022)

Commentationes Mathematicae Universitatis Carolinae

We show in ZF that: (i) Every subcompact metrizable space is completely metrizable, and every completely metrizable space is countably subcompact. (ii) A metrizable space 𝐗 = ( X , T ) is countably compact if and only if it is countably subcompact relative to T . (iii) For every metrizable space 𝐗 = ( X , T ) , the following are equivalent: (a) 𝐗 is compact; (b) for every open filter of 𝐗 , { F ¯ : F } ; (c) 𝐗 is subcompact relative to T . We also show: (iv) The negation of each of the statements, (a) every countably subcompact metrizable...

On subsets of Alexandroff duplicates

Takemi Mizokami (2005)

Commentationes Mathematicae Universitatis Carolinae

We characterize the subsets of the Alexandroff duplicate which have a G δ -diagonal and the subsets which are M-spaces in the sense of Morita.

On subspaces of pseudo-radial spaces

Jin Yuan Zhou (1993)

Commentationes Mathematicae Universitatis Carolinae

It is proved that, under the Martin’s Axiom, every T 1 -space with countable tightness is a subspace of some pseudo-radial space. We also give several characterizations of subspaces of pseudo-radial spaces and conclude that being a subspace of a pseudo-radial space is a local property.

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