Authors
Robert Goldblatt
Ian Hodkinson
Yde Venema
Date (dd-mm-yyyy)
2003
Title
On canonical modal logics that are not elementarily determined
Journal
Logique et Analyse
Volume
46
Publication Year
2003
Pages
77-101
Issue number
181
Document type
Article
Abstract

There exist modal logics that are validated by their canonical frames but are not sound and complete for any elementary class of frames. Continuum many such bimodal logics are exhibited, including one of each degree of unsolvability, and all with the finite model property. Monomodal examples are also constructed that extend K4 and are related to the proof of non-canonicity of the McKinsey axiom. We dedicate this paper to Max Cresswell, a pioneer in the study of canonicity, on the occasion of his 65th birthday.

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https://hdl.handle.net/11245.1/4b91da6d-0aca-4512-b186-bd2ffeb03244