Chettah et Djoweyda, Ouafa et Ferahtia
(Faculty of Mathematics and Informatics Department of Mathematics - Option : Algebra and Discrete Mathematics, 2021)
In this thesis. First, we present the concept of (crisp) fuzzy sets and their operations. Second, we introuduce the notion of intuitionistic fuzzy sets and lattice L-fuzzy sets.Moreover, we study the theory of soft sets. ...