Relevant logics, modal logics and theory change

Abstract

This thesis is a contribution to applied relevant logics. In Part One relevant logics are presented proof-theoretically and semantically. These logics are then extended to modal logics. Completeness proofs for all of the logics presented in Part One are provided. In Part Two, the logics of Part One are applied to certain problems in philosophical logic and Artificial Intelligence. Deontic and epistemic logics based on relevant logics are presented in chapter three and chapter four contains an extensive investigation of the logic of theory change (or database updating).