Abstract : Cs\'{a}sz\'{a}r [3] introduced the notions of $\gamma$-compact and $\gamma$-opera-tion on a topological space. In this paper, we introduce the notions of almost $\Gamma$-compact, $(\gamma, \tau)$-continuous function and $(\gamma, \tau)$-open function defined by $\gamma$-operation on a topological space and investigate some properties for such notions.
