Volume 34 • Number 1 • 2011   • Fuzzy Quasi-Ideals of Ordered Semigroups Muhammad Shabir and Asghar Khan Abstract. In this paper, we characterize ordered semigroups in terms of fuzzy quasi-ideals. We characterize left simple, right simple and completely regular ordered semigroups in terms of fuzzy quasi-ideals. We define semiprime fuzzy quasi-ideal of ordered semigroups and characterize completely regular ordered semigroup in terms of semiprime fuzzy quasi-ideals. We also study the decomposition of left and right simple ordered semigroups having the property \(a\leq a^{2}\) for all \(a\in S\), by means of fuzzy quasi-ideals. 2010 Mathematics Subject Classification: 06F05, 06D72, 08A72. Full text: PDF