Abstract

Operators which map subsets of a given set to the set of their minimal elements with respect to some relation R form the basis of a semanticapproach in non-monotonic logic, belief revision, conditional logic and updating. In this paper we investigate operators of this type from an algebraicviewpoint. A representation theorem is proved and various properties of theresulting algebras are investigated. It is shown that they behave quite differently from known algebras related to logics, e.g. modal algebras and Heytingalgebras