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Related papers: Selectively pseudocompact groups without non-trivi…

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A topological group is locally pseudocompact if it contains a non-empty open set with pseudocompact closure. In this note, we prove that if G is a group with the property that every closed subgroup of G is locally pseudocompact, then G_0 is…

General Topology · Mathematics 2011-09-27 Dikran Dikranjan , Gábor Lukács

We prove that the group G=Hom(P,Z) of all homomorphisms from the Baer-Specker group P to the group Z of integer numbers endowed with the topology of pointwise convergence contains no infinite compact subsets. We deduce from this fact that…

General Topology · Mathematics 2017-05-18 Maria Vincenta Ferrer , Salvador Hernández , Dmitri Shakhmatov

We work in set-theory without choice ZF. Denoting by AC(N) the countable axiom of choice, we show in ZF+AC(N) that the closed unit ball of a uniformly convex Banach space is compact in the convex topology (an alternative to the weak…

Functional Analysis · Mathematics 2008-12-18 Marianne Morillon

Topological groups whose underlying spaces are basically disconnected, $F$-, or $F'$-spaces but not $P$-spaces are considered. It is proved, in particular, that the existence of a Lindel\"of basically disconnected topological group which is…

General Topology · Mathematics 2022-08-18 Ol'ga Sipacheva

A discrete subset $S$ of a topological group $G$ is called a {\it suitable set} for $G$ if $S\cup \{e\}$ is closed in $G$ and the subgroup generated by $S$ is dense in $G$, where $e$ is the identity element of $G$. In this paper, the…

General Topology · Mathematics 2026-04-23 Fucai Lin , Jiamin He , Jiajia Yang , Chuan Liu

We study algebraic properties on a group G such that if the discrete group G has these properties then every locally compact shift continuous topology on G with adjoined zero is either compact, or discrete. We introduce electorally flexible…

Group Theory · Mathematics 2020-06-30 Kateryna Maksymyk

(1) Every infinite, Abelian compact (Hausdorff) group K admits 2^|K|-many dense, non-Haar-measurable subgroups of cardinality |K|. When K is nonmetrizable, these may be chosen to be pseudocompact. (2) Every infinite Abelian group G admits a…

General Topology · Mathematics 2013-10-09 W. W. Comfort , S. U. Raczkowski , F. J. Trigos-Arrieta

In 1990, Comfort asked: is there, for every cardinal number $\alpha \leq 2^{\mathfrak{c}}$, a topological group $G$ such that $G^\gamma$ is countably compact for all cardinals $\gamma<\alpha$, but $G^\alpha$ is not countably compact? A…

General Topology · Mathematics 2022-11-29 Artur Hideyuki Tomita , Juliane Trianon-Fraga

We prove that the existence of $\mathfrak{c}$ incomparable selective ultrafilters implies the existence of a Wallace semigroup whose cube is countably compact. In addition, assuming the existence of $2^{\mathfrak c}$ incomparable selective…

General Topology · Mathematics 2022-10-19 J. L. J. Fuentes-Maguiña , A. H. Tomita

It is shown that there exists a complete, atomless, sigma-centered Boolean algebra, which does not contain any regular countable subalgebra if and only if there exist a nowhere dense ultrafilter. Therefore the existence of such algebras is…

Logic · Mathematics 2016-09-07 Aleksander Błaszczyk , Saharon Shelah

If $\mathcal P$ is a family of filters over some set $I$, a topological space $X$ is \emph{sequencewise $\mathcal P$-\brfrt compact} if, for every $I$-indexed sequence of elements of $X$, there is $F \in \mathcal P$ such that the sequence…

General Topology · Mathematics 2016-08-30 Paolo Lipparini

A group $G$ is called hereditarily non-topologizable if, for every $H\le G$, no quotient of $H$ admits a non-discrete Hausdorff topology. We construct first examples of infinite hereditarily non-topologizable groups. This allows us to prove…

Group Theory · Mathematics 2013-10-02 A. A. Klyachko , A. Yu. Olshanskii , D. V. Osin

We present a contribution to the structure theory of locally compact groups. The emphasis is on compactly generated locally compact groups which admit no infinite discrete quotient. It is shown that such a group possesses a characteristic…

Group Theory · Mathematics 2012-07-10 Pierre-Emmanuel Caprace , Nicolas Monod

Answering a question raised by V. V. Tkachuk, we present several examples of $\sigma$-compact spaces, some only consistent and some in ZFC, that are not countably tight but in which the closure of any discrete subset is countably tight. In…

General Topology · Mathematics 2024-11-08 István Juhász , Jan van Mill

Under $\mathfrak{p} = \mathfrak{c}$, we answer Question 24 of \cite{dikranjan&shakhmatov3} for cardinality ${\mathfrak c}$ , by showing that if a non-torsion Abelian group of size continuum admits a countably compact Hausdorff group…

We continue in this paper the study of locally minimal groups started in \cite{LocMin}. The minimality criterion for dense subgroups of compact groups is extended to local minimality. Using this criterion we characterize the compact abelian…

General Topology · Mathematics 2010-06-29 Lydia Aussenhofer , María Jesús Chasco , Dikran Dikranjan , Xabier Domínguez

Let H be a countable subgroup of the metrizable compact abelian group G and f:H -> T=R/Z a (not necessarily continuous) character of H. Then there exists a sequence (chi_n)_n of (continuous) characters of G such that lim_n chi_n(alpha) =…

General Topology · Mathematics 2007-05-23 Mathias Beiglböck , Christian Steineder , Reinhard Winkler

We obtain many results and solve some problems about feebly compact paratopological groups. We obtain necessary and sufficient conditions for such a group to be topological. One of them is the quasiregularity. We prove that each…

Group Theory · Mathematics 2020-08-05 Taras Banakh , Alex Ravsky

We prove that many completeness properties coincide in metric spaces, precompact groups and dense subgroups of products of separable metric groups. We apply these results to function spaces C_p(X,G) of G-valued continuous functions on a…

General Topology · Mathematics 2017-05-26 Alejandro Dorantes-Aldama , Dmitri Shakhmatov

Under Martin's Axiom we construct a Boolean countably compact topological group whose square is not countably pracompact.

General Topology · Mathematics 2020-03-09 Serhii Bardyla , Alex Ravsky , Lyubomyr Zdomskyy