Strongly $\sigma$-metrizable spaces are super $\sigma$-metrizable

Taras Banakh

A topological space $X$ is called strongly $\sigma$-metrizable if $X={\bigcup }_{n\in \omega }{X}_n$ for an increasing sequence $(X_n{)}_{n\in \omega }$ of closed metrizable subspaces such that every conver…