Ol'ga Sipacheva

activity

20212026

collaborators

4 papers

math.GN2026

Metrizable and Fréchet--Urysohn subgroups and linear subspaces of topological vector spaces

Arkady Leiderman, Evgenii Reznichenko, Ol'ga Sipacheva

For a normed space $E$ , we denote by $E_{w}$ and $E_{w^{*}}^{'}$ the space $E$ and its dual $E^{'}$ endowed with the weak topology $w$ and the weak $^{*}$ topology $w^{*}$ , respectively. It is we…

math.GN2026

$ϰ$ -Fréchet--Urysohn and Baire subgroups of free topological groups

Arkady Leiderman, Evgenii Reznichenko, Ol'ga Sipacheva

A topological space is $ϰ$ -Fréchet--Urysohn if every point in the closure of an open set $U$ is the limit of a sequence of points of $U$ . We prove that every $ϰ$ -Fr…

math.GN2025

Weird $R$ -Factorizable Groups

Evgenii Reznichenko, Ol'ga Sipacheva

The problem of the existence of non-pseudo- $ℵ_{1}$ -compact $R$ -factorizable groups is studied. It is proved that any such group is submetrizable and has weight larger th…

math.HO2021

Alexander Arhangel'skii

Ol'ga Sipacheva

This is the opening article of the abstract book of conference "Set-Theoretic Topology and Topological Algebra" in honor of professor Alexander Arhangelskii on the occasion of his…

Metrizable and Fréchet--Urysohn subgroups and linear subspaces of topological vector spaces

ϰ-Fréchet--Urysohn and Baire subgroups of free topological groups

Weird R-Factorizable Groups

Alexander Arhangel'skii

$ϰ$ -Fréchet--Urysohn and Baire subgroups of free topological groups

Weird $R$ -Factorizable Groups