similarity dh-algebras

In , b. gerla and i. leustean introduced the notion of similarity on mvalgebra. a similarity mv-algebra is an mv-algebra endowed with a binary operation s that veri es certain additional properties. also, chirtes in, study the notion of similarity on lukasiewicz-moisil algebras. in particular, strong similarity lukasiewicz-moisil algebras were de ned. in this paper we de ne and study the variety of similarity symmetric heyting algebras (or similarity dh-algebras), i.e. symmetric heyting algebras endowed with an operation of similarity s. these algebras are a generalization of strong similarity lukasiewicz-moisil algebras. in addition, we introduce a propositional calculus and prove this calculus has similarity dh-algebras as algebraic counterpart.