*Definition [#o3c6d7c5]
-A topological space (X, τ) is said to be λ-R_1 if for x, y in X with &ref(http://www.eaflux.com/imgtex/imgtex.fcgi?%5bres=100%5d%7b%5c%5b%20%5crm%7bCl%7d_%5clambda%28%5c%7bx%5c%7d%29%20%5c%5d%7d%25.png);  is a subset of U and &ref(http://www.eaflux.com/imgtex/imgtex.fcgi?%5bres=100%5d%7b%5c%5b%20%5crm%7bCl%7d_%5clambda%28%5c%7by%5c%7d%29%20%5c%5d%7d%25.png);  is a subset of V.

*Remark [#ba820300]
-See [[λ-closure]].

*Property [#h8295976]

*Reference [#sb489d0b]
-Caldas Miguel, Jafari Saeid, ''On some low separation axioms via λ-open and λ-closure operator.'',  Rend. Circ. Mat. Palermo (2) 54 (2005), no. 2, 195–208.