*Definition [#dfae2ff0]
-Let (X,T) be topological space and let A and B be subsets of X. We say that A is weakly separated from B iff there exists an open set &ref(http://www.eaflux.com/imgtex/imgtex.fcgi?%5bres=100%5d%7b%5c%5b%20G%5csupset%20A%20%5c%5d%7d%25.png); such that &ref(http://www.eaflux.com/imgtex/imgtex.fcgi?%5bres=100%5d%7b%5c%5b%20G%5ccap%20B=%5cemptyset%20%5c%5d%7d%25.png);.

*Definition 2 [#n4b20f02]
-Let (X,T) be topological space and let A and B be subsets of X. We say that A and B are weakly separated if and only if &ref(http://www.eaflux.com/imgtex/imgtex.fcgi?%5bres=100%5d%7b%5c%5b%20A%5csetminus%20B%5cmbox%7b%20and%20%7dB%5csetminus%20A%20%5c%5d%7d%25.png); are [[separated]].

*Reference [#zd72d63d]
:Definition|Aull, Charles E.; Thron, W.J.,''Separation axioms between T0 and T1.'', (English) [J] Nederl. Akad. Wet., Proc., Ser. A 65, 26-37 (1962).
:Definition 2|Zbigniew Karno , ''Separated and Weakly Separated Subspaces of Topological Spaces'', JOURNAL OF FORMALIZED MATHEMATICS Volume 4, Released 1992, Published 2003