*Definition [#xcc3bd02]
-A topological space (X,τ) is said to be semi-R_0 if every [[semi-open]] set contains the [[semi-closure]] of each of its singletons, that is, for each [[semi-open]] set O in X and each x in O, &ref(http://www.eaflux.com/imgtex/imgtex.fcgi?%5bres=100%5d%7b%5c%5b%20%5cmbox%7bs-cl%7d%28%5c%7bx%5c%7d%29%5csubset%20O%20%5c%5d%7d%25.png);.

*Property [#ac14a592]
-semi-R_0 ⇒ [[weakly semi-R_0]]. [2]

*Reference [#h2585d49]
+Caldas, M.; Georgiou, D. N.; Jafari, S. , ''Characterizations of low separation axioms via α-open sets and α-closure operator.'', (English summary) Bol. Soc. Parana. Mat. (3) 21 (2003), no. 1-2, 97–111.
+Arya, S.P.; Nour, T.M., ''Weakly semi-R_0 spaces.'', (English) [J] Indian J. Pure Appl. Math. 21, No.12, 1083-1085 (1990).