T_-1

Definition

• A topological space (X,τ) is a T_-1 space if for arbitrary three distinct points of X, one of them is weakly separated from one of the two other points.

Property

• T_-1 ⇒ S_R?.

Reference

• Guia, Josep The Sα separation axioms., (Serbo-Croatian summary), Mat. Vesnik 38 (1986), no. 1, 45–57.