English

Extensions of K5: Proof Theory and Uniform Lyndon Interpolation

Logic in Computer Science 2024-03-01 v1 Logic

Abstract

We introduce a Gentzen-style framework, called layered sequent calculi, for modal logic K5 and its extensions KD5, K45, KD45, KB5, and S5 with the goal to investigate the uniform Lyndon interpolation property (ULIP), which implies both the uniform interpolation property and the Lyndon interpolation property. We obtain complexity-optimal decision procedures for all logics and present a constructive proof of the ULIP for K5, which to the best of our knowledge, is the first such syntactic proof. To prove that the interpolant is correct, we use model-theoretic methods, especially bisimulation modulo literals.

Keywords

Cite

@article{arxiv.2307.11727,
  title  = {Extensions of K5: Proof Theory and Uniform Lyndon Interpolation},
  author = {Iris van der Giessen and Raheleh Jalali and Roman Kuznets},
  journal= {arXiv preprint arXiv:2307.11727},
  year   = {2024}
}

Comments

20-page conference paper + 5-page appendix with examples and proofs