A new calculus for intuitionistic Strong L\'ob logic: strong termination and cut-elimination, formalised

Autor: Shillito, Ian, van der Giessen, Iris, Goré, Rajeev, Iemhoff, Rosalie
Rok vydání: 2023
Předmět:
Druh dokumentu: Working Paper
Popis: We provide a new sequent calculus that enjoys syntactic cut-elimination and strongly terminating backward proof search for the intuitionistic Strong L\"ob logic $\sf{iSL}$, an intuitionistic modal logic with a provability interpretation. A novel measure on sequents is used to prove both the termination of the naive backward proof search strategy, and the admissibility of cut in a syntactic and direct way, leading to a straightforward cut-elimination procedure. All proofs have been formalised in the interactive theorem prover Coq.
Comment: 21-page conference paper + 4-page appendix with proofs
Databáze: arXiv