pre-T_2

Definition

• A space (X,τ) is called pre-T_2 iff to each pair of distinct points x, y of X, there exists a pair of disjoint pre-open? sets one containing x and the other containing y.

Property

• Every pre-T_2 space is pre-US.

Reference

• Athisaya Ponmani, S.; Lellis Thivagar, M., Another form of separation axioms. , (English) [J] Methods Funct. Anal. Topol. 13, No. 4, 380-385 (2007).