(2) x 2 ig(f¡1¡ig¡cg(V )¢¢) for every g-open subset V containing f(x).
(3) x 2 ig¡f¡1(V )¢for every gr-open subset V containing f(x).
(4) For any gr-open set V containing f(x), there exists a g-open set U
containing x such that f(U) j V .
Proof. (1) ) (2). Let V be any g-open subset of Y containing f(x).
From the denition of almost continuity, there exists a g-open subset U of X
containing x such that f(U) j ig¡cg(V )¢.
Since x 2 U j f¡1(ig¡cg(V )¢),we have x 2 ig(f¡1¡ig¡cg(V )¢¢).(2) ) (3). Let V be any gr-open subset of Y containing f(x). Then sinceV = cg(V )¢, by (2), we have x 2 ig¡f¡1(¢.(3) ) (4). Let V be any gr-open subset of Y containing f(x). From (3),
there exists a g-open set U containing x such that U j f¡1(V ). Hence we
have (4).(4) ) (1). Let V be any g-open subset of Y containing f(x). Then f(x)2 V j cg(¢. Since ig¡cg(V )¢is gr-open, by (4) there exists a g-openset U containing x such that f(U) j cg(V )¢. Hence f is almost (g; g0)-continuous. ¤