Abstract
The concept of quasi-coincidence of interval valued intuitionistic fuzzy point with an interval valued intuitionistic fuzzy set is considered. By using this idea, the notion of interval valued (alpha; beta)-intuitionistic fuzzy bi-ideals, (1,2) ideals in a semigroup introduced and consequently, a generalization of interval valued intuitionistic fuzzy bi-ideals and intuitionistic fuzzy bi-ideals is defined. In this paper, we study the related properties of the interval valued (alpha; beta)-intuitionistic fuzzy bi-ideals, (1,2) ideals and in particular, an interval valued (is an element of; is an element of Vq)- fuzzy bi-ideals and (1,2) ideals in semigroups will be investigated.