Fréchet–Urysohn Spaces and Groups
摘要
This chapter deals with topological (vector) spaces satisfying some sequential conditions. We study Fréchet–Urysohn spaces (i.e., spaces E such that for each \(A\subset E\) and each \(\mathrm {x}\in \mathrm {A}^{-}\) there exists a sequence in A converging to x). The main result states that every sequentially complete Fréchet–Urysohn lcs is a Baire space. Since every infinite-dimensional Montel (DF)-space E is non-metrizable and sequential, the following question arises: Is every Fréchet–Urysohn space in the class G metrizable?