Sequent Calculi with procedure calls
Résumé
In this paper, we study 3 focussed sequent calculi that are based on Miller-Liang's LKF system for polarised classical logic, and integrate the possibility to call a decision procedure for some background theory T . The main sequent calculus out of the three is LK(T), in which we prove cut-elimination. Changing the polarities of literals and connectives does not change the provability of formulae, only the shape of proofs. In order to prove this, we introduce a second sequent calculus, LK+(T ) that extends LK(T) with a relaxed focussing discipline. We then prove completeness of LK(T) (and therefore of LK+(T)) with respect to first-order reasoning modulo the ground propositional lemmas of the background theory T . A third sequent calculus is introduced, LKp(T), that extends LK(T) with the possibility to polarise literals "on the fly" during proof-search. This is used in other works to simulate the DPLL(T) procedure, and we show here its completeness. Encodings of LK+(T) and LKp(T) into the most restrictive system LK(T) are presented along the way.
Domaines
Logique en informatique [cs.LO]Origine | Fichiers produits par l'(les) auteur(s) |
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