Johan van Benthem Modal Frame Correspondences and Fixed - Points Dedicated to the memory of

Modal Frame Correspondences Generalized

Taking Löb's Axiom in modal provability logic as a running thread, we discuss some general methods for extending modal frame correspondences, mainly by adding fixedpoint operators to modal languages as well as their correspondence languages. Our suggestions are backed up by some new results – while we also refer to relevant work by earlier authors . But our main aim is advertizing the perspecti...

Frame Correspondences in Modal Predicate Logic

Understanding modal predicate logic is a continuing challenge, both philosophical and mathematical. In this paper, I study this system in terms of frame correspondences, finding a number of definability results using substitution methods, including new analyses of axioms in intermediate intuitionistic predicate logics. The semantic arguments often have a different flavour from those in proposit...

Modal Fixed-Point Logic and Changing Models

Dynamic logic for belief revision

We show how belief revision can be treated systematically in the format of dynamicepistemic logic, when operators of conditional belief are added. The core engine consists of definable update rules for changing plausibility relations between worlds, which have been proposed independently in the dynamic-epistemic literature on preference change. Our analysis yields two new types of modal result....

Minimal predicates, fixed-points, and definability

Minimal predicates P satisfying a given first-order description (P) occur widely in mathematical logic and computer science. We give an explicit first-order syntax for special first-order 'PIA conditions' (P) which guarantees unique existence of such minimal predicates. Our main technical result is a preservation theorem showing PIA-conditions to be expressively complete for all those first-ord...