Characterized subgroups of topological abelian groups

Dikran Dikranjan, Anna Giordano Bruno, Daniele Impieri

A subgroup $H$ of a topological abelian group $X$ is said to be characterized by a sequence $\mathbf{v}=(v_n)$ of characters of $X$ if $H=\{x\in X:v_n(x)\to 0\ \text{in}\ \mathbb T…