On the Urysohn number of a topological space II

Abstract

Some variations of Arhangel’skii inequality |X| ≤ 2x^(X)L(X) for every Hausdorff space X [3], given in [2] and [6] are improved.

Keywords: Urysohn number, θ -closure, θ -closed hull.

Quaestiones Mathematicae 37(2014), 445–449