# Semantic characterization of Kracht formulas

Kikot, Stanislav
(2010)
Semantic characterization of Kracht formulas.
In:
Beklemishev, L.D. and Goranko, V. and Shehtman, V. (eds.)
*Advances in Modal Logic.*
London, UK:
College Publications, pp. 218-234.
ISBN 9781848900134.

## Abstract

Kracht formulas are first-order correspondents of modal Sahlqvist formulas. In this paper we present a model theoretic characterization of Kracht formulas similar to Van Benthem's theorem saying that a rst-order formula is equivalent to a modal formula is it is invariant under bisimulation. Our characterization yields a method to prove that a given first-order formula is not equivalent to any Kracht formula. In particular, we prove that the first-order formula, expressing the `cubic property' of a 3-dimensional modal frame does not have a Kracht equivalent.

## Metadata

Item Type: | Book Section |
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Keyword(s) / Subject(s): | Kracht formulas, semantic characterization, Kracht-simulation |

School: | Birkbeck Faculties and Schools > Faculty of Science > School of Computing and Mathematical Sciences |

Depositing User: | Sarah Hall |

Date Deposited: | 30 May 2013 08:12 |

Last Modified: | 09 Aug 2023 12:33 |

URI: | https://eprints.bbk.ac.uk/id/eprint/7073 |

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