Ockham algebras with demi-pseudocomplementation

Abstract

The variety dpk _1,1 consists of those algebras (L;⋁,⋀,f,^*,0,1) of type (2,2,1,1,0,0) where (L;⋁,⋀,f,0,1) is an Ockham algebra in which f ³ = f, (L;⋁,⋀,^*,0,1) is a demi-pseudocomplemented lattice, and the unary operations f and ^* commute. Here we give a description of the structure of the lattice of congruences of a subdirectly irreducible algebra in dpk _1,1.