The Variety of Semi-Heyting Algebras Satisfying the Equation (0 -->1)*V(0-->1)**=1.

ABAD MANUEL; CORNEJO JUAN MANUEL; DÍAZ VARELA JOSÉ PATRICIO

Reports on mathematical logic

Jagiellonian University Press

Lugar: KRAKOW ; Año: 2009

0137-2904

In [4, Denition 8.1], some important subvarieties of the variety SH of Semi-Heytingalgebras are dened. The purpose of this paper is to introduce and investigate the subvarietyISSH of SH, characterized by the identity   (0 -->1)*V(0-->1)**=1. We prove that ISSH contains all the subvarieties introduced by Sankappanavar and it is in fact the least subvarietyof SH with this property. We also determine the sublattice generated by the subvarietiesintroduced in [4, Denition 8.1] within the lattice of subvarieties of semi-Heyting algebras.