Commutative pseudo-equality algebras

Pseudo equality algebras were initially introduced by Jenei and Kóródi as a possible algebraic semantic for fuzzy type theory, and they have been revised by Dvurečenskij and Zahiri under the name of JK-algebras. In this paper we define and study the commutative pseudo equality algebras. We give a characterization of commutative pseudo equality algebras and we prove that an invariant pseudo equality algebra is commutative if and only if its corresponding pseudo BCK(pC)-meet-semilattice is commutative. Other results consist of proving that every commutative pseudo equality algebra is a distributive lattice and every finite invariant commutative pseudo equality algebra is a symmetric pseudo equality algebra. We also introduce and investigate the commutative deductive systems of pseudo equality algebras. As applications of these notions and results we define and study the measures and measure-morphisms on pseudo equality algebras, we prove new properties of state pseudo equality algebras, and we introduce and investigate the pseudo-valuations on pseudo equality