*Definition [#rd68ab1f]
-A subset A of X with an [[operation]] γ on τ is called γ-open if for each x ∈ A, there exists an open set U such that x ∈ U and &ref(http://www.eaflux.com/imgtex/imgtex.fcgi?%5bres=100%5d%7b%5c%5b%20U%5e%5cgamma%5csubset%20A%20%5c%5d%7d%25.png);.

*Remark [#q6885c01]
-&ref(http://www.eaflux.com/imgtex/imgtex.fcgi?%5bres=100%5d%7b%5c%5b%20V%5e%5cgamma%20%5c%5d%7d%25.png); denotes the value of γ at V ∈ τ .

*Reference [#wb5bcb2c]
-Basu, C. K.; Afsan, B. M. Uzzal; Ghosh, M. K., ''A class of functions and separation axioms with respect to an operation.'' (English summary), Hacet. J. Math. Stat. 38 (2009), no. 2, 103-118.