Definition
- A topological space (X,τ) is said to be semi-R_1 if for each pair x,y in X such that , there exist disjoint semi open?sets U and V such that .
Reference
- Dorsett, C., Images and hyperspaces of s-essentially T_1 and s-essentially T_2 spaces and semitopological properties. (Serbo-Croatian summary), Glas. Mat. Ser. III 21(41) (1986), no. 2, 415–422.