Internal Definability And Completeness In Modal Logic
Marcus Kracht · 1990
4Dedicated to my parents, Susanne Kracht and Alfred Kracht, to my sister Ina and my brother Martin Three pillars of wisdom support the edifice of Modal Logic. There is the ubiquitous Completeness Theory, the present Correspondency—or, more generally, Definability Theory – and finally, the Duality Theory between Kripke-frames and ‘modal algebras ’ has become an area of its own. [...] The relation between correspondency and completeness [...] turns out to be rather complex—and indeed only partially understood. J. van Benthem