Abstract
In this paper, we give the concepts of generalized interval valued fuzzy subsemigroups, which are generalizations of the notion of interval valued fuzzy subsemigroups and of (ᾱ, β)-interval valued fuzzy subsemigroups, where ᾱ ≺ β. Also we prove some of related properties of generalized interval valued fuzzy quasi-ideals on semigroups. In the main results, we characterize regular and intra-regular semigroups in terms of generalized interval valued fuzzy ideal and quasi-ideals.