Benouarith et Feidjel, Fatiha et Djawhar2020-10-182020-10-182020https://repository.univ-msila.dz/handle/123456789/19970The subject of memoire is written within the framework of the extention of fuzzy sets, we study the basic concepts and characteristics of multi-fuzzy sets. Also, particular classes of this concept.enCrisp set, Fuzzy set, Extension of fuzzy sets, Multi-fuzzy set.Thesis