Completing the Picture: Complexity of Graded Modal Logics with Converse

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Abstract

A complete classification of the complexity of the local and global satisfiability problems for graded modal language over traditional classes of frames has already been established. By “traditional” classes of frames, we mean those characterized by any positive combination of reflexivity, seriality, symmetry, transitivity, and the Euclidean property. In this paper, we fill the gaps remaining in an analogous classification of the graded modal language with graded converse modalities. In particular, we show its NExpTime-completeness over the class of Euclidean frames, demonstrating this way that over this class the considered language is harder than the language without graded modalities or without converse modalities. We also consider its variation disallowing graded converse modalities, but still admitting basic converse modalities. Our most important result for this variation is confirming an earlier conjecture that it is decidable over transitive frames. This contrasts with the undecidability of the language with graded converse modalities.

Details

Original languageEnglish
Pages (from-to)493-520
Number of pages28
JournalTheory and practice of logic programming
Volume21
Issue number4
Publication statusPublished - 1 Apr 2021
Peer-reviewedNo

External IDs

Scopus 85105173816
Mendeley e95574dd-2a5b-3de3-98e4-cae4023ba315

Keywords