On January 24, we will have a LIRa session with Sebastian Enqvist.
Everyone is cordially invited!
Speaker: Sebastian Enqvist (Lund University)
Title: A Lindström theorem for a class of normal modal logics
Date and Time: Thursday, January 24, 2013, 15:30-17:30
Venue: Science Park 904, Room A1.04
I present a Lindström-style characterization theorem for normal modal logics corresponding to classes of frames that are definable by sets of strict universal Horn formulas. The result is shown to be a generalization of a recent characterization result for modal logic with the global modality. The relationship with earlier characterization results for basic modal logic is discussed, as well as a negative result showing that the characterization result cannot be extended to cover every elementary class of frames.