A non-uniform view of Craig interpolation in modal logics with linear frames

Fuente: arXiv
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Main Authors: Kurucz, Agi, Wolter, Frank, Zakharyaschev, Michael
Format: Preprint
Published: 2023
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author Kurucz, Agi
Wolter, Frank
Zakharyaschev, Michael
author_facet Kurucz, Agi
Wolter, Frank
Zakharyaschev, Michael
contents Normal modal logics extending the logic K4.3 of linear transitive frames are known to lack the Craig interpolation property, except some logics of bounded depth such as S5. We turn this `negative' fact into a research question and pursue a non-uniform approach to Craig interpolation by investigating the following interpolant existence problem: decide whether there exists a Craig interpolant between two given formulas in any fixed logic above K4.3. Using a bisimulation-based characterisation of interpolant existence for descriptive frames, we show that this problem is decidable and coNP-complete for all finitely axiomatisable normal modal logics containing K4.3. It is thus not harder than entailment in these logics, which is in sharp contrast to other recent non-uniform interpolation results. We also extend our approach to Priorean temporal logics (with both past and future modalities) over the standard time flows-the integers, rationals, reals, and finite strict linear orders-none of which is blessed with the Craig interpolation property.
format Preprint
id arxiv_https___arxiv_org_abs_2312_05929
institution arXiv
publishDate 2023
record_format arxiv
spellingShingle A non-uniform view of Craig interpolation in modal logics with linear frames
Kurucz, Agi
Wolter, Frank
Zakharyaschev, Michael
Logic
Logic in Computer Science
03B45 (Primary) 03C40 (Secondary)
Normal modal logics extending the logic K4.3 of linear transitive frames are known to lack the Craig interpolation property, except some logics of bounded depth such as S5. We turn this `negative' fact into a research question and pursue a non-uniform approach to Craig interpolation by investigating the following interpolant existence problem: decide whether there exists a Craig interpolant between two given formulas in any fixed logic above K4.3. Using a bisimulation-based characterisation of interpolant existence for descriptive frames, we show that this problem is decidable and coNP-complete for all finitely axiomatisable normal modal logics containing K4.3. It is thus not harder than entailment in these logics, which is in sharp contrast to other recent non-uniform interpolation results. We also extend our approach to Priorean temporal logics (with both past and future modalities) over the standard time flows-the integers, rationals, reals, and finite strict linear orders-none of which is blessed with the Craig interpolation property.
title A non-uniform view of Craig interpolation in modal logics with linear frames
topic Logic
Logic in Computer Science
03B45 (Primary) 03C40 (Secondary)
url https://arxiv.org/abs/2312.05929