*Definition [#lc06816d]
-Let (X,τ)　be a topological space. X is said to be weakly pre-R_0 if &ref(http://www.eaflux.com/imgtex/imgtex.fcgi?%5bres=100%5d%7b%5c%5b%20%5ccap_%7bx%5cin%20X%7d%5c!%5c%20%5cmathrm%7bs%7d%5cmbox%7b-%7d%5cmathrm%7bcl%7d%28%5c%7bx%5c%7d%29=%5cemptyset%20%5c%5d%7d%25.png);.

*Reference [#wbffd3ad]
-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.