Brahim ZIANE2021-02-012021-02-012021http://dspace.univ-msila.dz:8080//xmlui/handle/123456789/23558In this thesis, we consider the problem of representation and construction of intuitionistic fuzzy preorders and weak orders, where many fundamental representations result extending those of Ulrich Bodenhofer et al are presented. Moreover, we study the concept of intuitionistic fuzzy sublattices and intuitionistic fuzzy ideals with respect to an intuitionistic fuzzy t-norm on an adequate lattice. Some characterizations and properties of these intuitionistic fuzzy sublattices and ideals with respect to an intuitionistic fuzzy t-norm are established.Intuitionistic fuzzy set, intuitionistic fuzzy ordering relation, intuitionistic fuzzy equivalence relation, intuitionistic fuzzy weak order, intuitionistic fuzzy t-norm, residuated lattice.Thesis