INTUITIONISTIC SAHLQVIST THEORY FOR DEDUCTIVE SYSTEMS
Damiano Fornasiere, Tommaso Moraschini · Journal of Symbolic Logic · 2023
Abstract Sahlqvist theory is extended to the fragments of the intuitionistic propositional calculus that include the conjunction connective. This allows us to introduce a Sahlqvist theory of intuitionistic character amenable to arbitrary protoalgebraic deductive systems. As an application, we obtain a Sahlqvist theorem for the fragments of the intuitionistic propositional calculus that include the implication connective and for the extensions of the intuitionistic linear logic.