A Categorical Equivalence for Tense Nelson Algebras

A Categorical Equivalence for Product Algebras

Categorical equivalence of some algebras

We show that two lattices are categorically equivalent if and only if they are isomorphic or dually isomorphic. Two normal bands are categorically equivalent if and only if they are isomorphic or antiisomorphic. The same result holds for finite bands as well. We also obtain corollaries for rectangular bands and semilattices.

Categorical Equivalence of Algebras with a Majority Term

Let A be a finite algebra with a majority term. We characterize those algebras categorically equivalent to A. The description is in terms of a derived structure with universe consisting of all subalgebras of A × A, and with operations of composition, converse and intersection. The main theorem is used to get a different sort of characterization of categorical equivalence for algebras generating...

Tense like equality algebras

In this paper, first we define the notion of involutive operator on bounded involutive equality algebras and by using it, we introduce a new class of equality algebras that we called it a tense like equality algebra. Then we investigate some properties of tense like equality algebra. For two involutive bounded equality algebras and an equality homomorphism between them, we prove that the tense ...

Characterisations of Nelson Algebras

Nelson algebras arise naturally in algebraic logic as the algebraic models of Nelson’s constructive logic with strong negation. This note gives two characterisations of the variety of Nelson algebras up to term equivalence, together with a characterisation of the finite Nelson algebras up to polynomial equivalence. The results answer a question of Blok and Pigozzi and clarify some earlier work ...