The Cartesian product of any family of $W$-spaces is $κ$-Fréchet-Urysohn

Abstract

In this note, we prove that an arbitrary product of $W$-spaces is a $κ$-Fréchet-Urysohn space. We also show that the boundary tightness of a product $X \times Y$ is at most $κ$ provided that $X$ is compact with tightness $t(X) \leq κ$ and $Y$ has boundary tightness $tb(Y) \leq κ$. The first result fully resolves, and the second partially addresses, two questions recently raised by Tkachuk.