*Definition [#p6991417]
-A topological space (X,τ) is said to be λ-D_2 if for any x, y ∈ X such that &ref(http://www.eaflux.com/imgtex/imgtex.fcgi?%5bres=100%5d%7b%5c%5b%20x%5cneq%20y%20%5c%5d%7d%25.png);  there
exist disjoint [[λ-D-sets>λ-Difference set]] G and E such that x ∈ G and y ∈ E.

*Property [#g697e12d]
-λ_D_2 ⇔ [[λ-D_1]].

*Reference [#k6b3ff0b]
-Caldas Miguel, Jafari Saeid, Navalagi Govindappa, ''More on λ-closed sets in topological spaces.'',Rev. Colombiana Mat. 41 (2007), no. 2, 355-369.