C_R

Definition

• A topological space (X,τ) is said to be C_R if for every x∈X, {x}' does not contain a non-empty closed set.

Proposition

• A topological space (X,τ) is C_R iff it is a R_0 space.

Reference

• Guia, Josep, Essentially T_D and essentially T_UD spaces., Bull. Math. Soc. Sci. Math. R. S. Roumanie (N.S.) 32(80) (1988), no. 3, 227-233.