ii- Open Set in Bitopological Spaces

In this paper, we define ii-open set in bitopological space as follows: Let ( , , ) be a bitopological space, a subset A of is said to be ( ii- open set ) if there exist U,V and U,V such that:
A=int1(U) or A=int2 (V)
A or A
We study some characterizations and properties of this class. Also, we explain the relation between ii- open sets and open sets, i-open sets and -open sets in bitopological space. Furthermore, we define ii- continuous mapping on bitopological spaces with some properties.