T_{ES}

Last-modified: 2013-04-19 (金) 13:15:36

Definition

  • A topological space (X,τ) said to be a T_{ES} if every singleton subset of X is either open or closed.

Property

  • T_{ES} ⇒ T_D.
  • T_{ES} ⇒ T_F.

Reference

  • McSherry, D. M. G. , On separation axioms weaker than T_1. , Proc. Roy. Irish Acad. Sect. A 74 (1974), 115–118.