Calcul pratique du treillis de Galois d'une correspondance
A characterization of regular lattices of fuzzy sets and their isomorphisms is given in Part I. A characterization of involutions on regular lattices of fuzzy sets and the isomorphisms of De Morgan algebras of fuzzy sets is given in Part II. Finally all classes of De Morgan algebras of fuzzy sets with respect to isomorphisms are completely described.
We consider rings equipped with a closure operation defined in terms of a collection of commuting idempotents, generalising the idea of a topological closure operation defined on a ring of sets. We establish the basic properties of such rings, consider examples and construction methods, and then concentrate on rings which have a closure operation defined in terms of their lattice of central idempotents.
Cet article constitue une présentation unifiée des principales méthodes de construction du treillis de Galois d'une correspondance. Nous rappelons d'abord sa définition, puis nous décrivons quatre algorithmes de construction des éléments du treillis qui sont les rectangles maximaux de la relation binaire. Ces algorithmes ne sont pas originaux. Les descriptions précises de algorithmes, le plus souvent absentes des publications originales, permettent une programmation simple, dans un langage procédural...
Necessary and sufficient conditions under which two fuzzy sets (in the most general, poset valued setting) with the same domain have equal families of cut sets are given. The corresponding equivalence relation on the related fuzzy power set is investigated. Relationship of poset valued fuzzy sets and fuzzy sets for which the co-domain is Dedekind-MacNeille completion of that posets is deduced.