Hernán Javier San Martín

Frontal Operators in Weak Heyting Algebras

In this paper we shall introduce the variety FWHA of frontal weak Heyting algebras as a generalization of the frontal Heyting algebras introduced by Leo Esakia in [10]. A frontal operator in a weak Heyting algebra A is an expansive operator τ preserving finite meets which also satisfies the equation

Principal congruences in weak Heyting algebras

{\tau(a) \leq b \vee (b \rightarrow a)}

The logic Ł

, for all

The left adjoint of Spec from a category of lattice-ordered groups

{a, b \in A}

Errata on “On the Variety of Heyting Algebras with Successor Generated by all Finite Chains”

. These operators were studied from an algebraic, logical and topological point of view by Leo Esakia in [10]. We will study frontal operators in weak Heyting algebras and we will consider two examples of them. We will give a Priestley duality for the category of frontal weak Heyting algebras in terms of relational spaces