Internal models for coalgebraic modal logics

Abstract

We present ongoing work into the systematic study of the use of dual adjunctions in coalgebraic modal logic. We introduce a category of internal models for a modal logic. These are constructed from syntax, and yield a generalised notion of canonical model. Further, expressivity of a modal logic is shown to be characterised by factorisation of its models via internal models and the existence of cospans of internal models. © 2012 IFIP International Federation for Information Processing.