In 1937, Stone [6] introduced and investigated the regular open sets. These sets are contained in the family of open sets since a set is regular open if it is equal to the interior of its closure. In 1978, Cameron [2] also introduced and investigated the concept of a regular semiopen set. A set A is regular semiopen if there is a regular open set U such that U ⊆ A ⊆ U . In 2007, a new class of ...

The purpose of this paper is to introduce and study regular bopen sets (briefly rb-open sets) in topological spaces and obtain some of their properties. We introduce the rb-closure and discuss some basic properties of the rb-closure. Also we study the new concepts of rb-closed spaces by means of filter bases. Mathematics Subject Classification: 54A05, 54A20

In this article we introduce the notion of fuzzy b-locally open (bLO) sets, fuzzy bLO sets, fuzzy bLO sets in fuzzy bitopological spaces and obtain several characterizations and some properties of these sets. Also we introduce the notion of fuzzy b-locally continuous functions on bitopological spaces.

In this paper, a collection of sets are investigated in such way that the splits preopen and b-open also semi-open sets. Functions terms is part paper it will be considered these remains invariant under homeomorphic image.