ii - open sets in topological spaces

In this paper, we introduce a new class of open sets in a topological space called ii − open sets. We study some properties and several characterizations of this class, also we explain the relation of ii − open sets with many other classes of open sets. Furthermore, we define iw − closed sets and iiw − closed sets and we give some fundamental properties and relations between these classes and other classes such as w − closed and αw − closed sets.