Two-variable Logic with Counting and a Linear Order

We study the finite satisfiability problem for the two-variable fragment of first-order logic extended with counting quantifiers (C2) and interpreted over linearly ordered structures. We show that the problem is undecidable in the case of two linear orders (in the presence of two other binary symbol...

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Main Authors: Witold Charatonik, Piotr Witkowski
Format: Article
Language:English
Published: Logical Methods in Computer Science e.V. 2016-06-01
Series:Logical Methods in Computer Science
Subjects:
Online Access:https://lmcs.episciences.org/1640/pdf
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author Witold Charatonik
Piotr Witkowski
author_facet Witold Charatonik
Piotr Witkowski
author_sort Witold Charatonik
collection DOAJ
description We study the finite satisfiability problem for the two-variable fragment of first-order logic extended with counting quantifiers (C2) and interpreted over linearly ordered structures. We show that the problem is undecidable in the case of two linear orders (in the presence of two other binary symbols). In the case of one linear order it is NEXPTIME-complete, even in the presence of the successor relation. Surprisingly, the complexity of the problem explodes when we add one binary symbol more: C2 with one linear order and in the presence of other binary predicate symbols is equivalent, under elementary reductions, to the emptiness problem for multicounter automata.
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spelling doaj.art-bd834f6057fc473a8de9d11e7a85a2622024-03-08T09:43:58ZengLogical Methods in Computer Science e.V.Logical Methods in Computer Science1860-59742016-06-01Volume 12, Issue 210.2168/LMCS-12(2:8)20161640Two-variable Logic with Counting and a Linear OrderWitold CharatonikPiotr Witkowskihttps://orcid.org/0000-0002-1908-0827We study the finite satisfiability problem for the two-variable fragment of first-order logic extended with counting quantifiers (C2) and interpreted over linearly ordered structures. We show that the problem is undecidable in the case of two linear orders (in the presence of two other binary symbols). In the case of one linear order it is NEXPTIME-complete, even in the presence of the successor relation. Surprisingly, the complexity of the problem explodes when we add one binary symbol more: C2 with one linear order and in the presence of other binary predicate symbols is equivalent, under elementary reductions, to the emptiness problem for multicounter automata.https://lmcs.episciences.org/1640/pdfcomputer science - logic in computer science
spellingShingle Witold Charatonik
Piotr Witkowski
Two-variable Logic with Counting and a Linear Order
Logical Methods in Computer Science
computer science - logic in computer science
title Two-variable Logic with Counting and a Linear Order
title_full Two-variable Logic with Counting and a Linear Order
title_fullStr Two-variable Logic with Counting and a Linear Order
title_full_unstemmed Two-variable Logic with Counting and a Linear Order
title_short Two-variable Logic with Counting and a Linear Order
title_sort two variable logic with counting and a linear order
topic computer science - logic in computer science
url https://lmcs.episciences.org/1640/pdf
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