Logic seminar

Pantelis Eleftheriou, Department of Pure Mathematics, University of Waterloo

“Model-theoretic constructions in many-valued modal logics”

We study a family of Heyting-valued modal logics introduced by Fitting in the early ’90s. For each logic in this family, the semantics is given via Kripke-frames whose edges are labelled with values from an underlying Heyting algebra H. If H is finite, the semantics corresponds to a multiple-expert semantics of interest to Knowledge Representation, where every value of H defines a group of experts.
We generalize four model-theoretic constructions from modal logic to this setting and prove truth- invariance results under these constructions. If H is finite, the truth-invariance results correspond to invariance of the epistemic consensus of the predefined group of experts.
This is joint work with C. Koutras.