An extension of Kracht's theorem to generalized Sahlqvist formulas
Logic
2010-03-15 v1
Abstract
Sahlqvist formulas are a syntactically specified class of modal formulas proposed by Hendrik Sahlqvist in 1975. They are important because of their first-order definability and canonicity, and hence axiomatize complete modal logics. The first-order properties definable by Sahlqvist formulas were syntactically characterized by Marcus Kracht in 1993. The present paper extends Kracht's theorem to the class of `generalized Sahlqvist formulas' introduced by Goranko and Vakarelov and describes an appropriate generalization of Kracht formulas.
Keywords
Cite
@article{arxiv.1003.2603,
title = {An extension of Kracht's theorem to generalized Sahlqvist formulas},
author = {Stanislav Kikot},
journal= {arXiv preprint arXiv:1003.2603},
year = {2010}
}