The inverse method is a saturation-based theorem-proving technique; it relies on a forward proof-search strategy and can be applied to cut-free calculi enjoying the subformula property. Here, we apply this method to derive the unprovability of a goal formula G in Intuitionistic Propositional Logic. To this aim we design a forward calculus FRJ(G) for Intuitionistic unprovability, which is appropriate for constructively ascertaining the unprovability of a formula G by providing a concise countermodel for it; in particular, we prove that the generated countermodels have minimal height. Moreover, we clarify the role of the saturated database obtained as result of a failed proof-search in FRJ(G) by showing how to extract from such a database a derivation witnessing the Intuitionistic validity of the goal.
Duality between Unprovability and Provability in Forward Refutation-search for Intuitionistic Propositional Logic / C. Fiorentini, M. Ferrari. - In: ACM TRANSACTIONS ON COMPUTATIONAL LOGIC. - ISSN 1529-3785. - 21:3(2020), pp. 22.1-22.47.
Titolo: | Duality between Unprovability and Provability in Forward Refutation-search for Intuitionistic Propositional Logic |
Autori: | |
Parole Chiave: | Proof-search procedures; intuitionistic propositional logic; sequent calculi |
Settore Scientifico Disciplinare: | Settore INF/01 - Informatica Settore MAT/01 - Logica Matematica |
Data di pubblicazione: | 2020 |
Rivista: | |
Tipologia: | Article (author) |
Digital Object Identifier (DOI): | http://dx.doi.org/10.1145/3372299 |
Appare nelle tipologie: | 01 - Articolo su periodico |
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