Herbrand-Confluence

We consider cut-elimination in the sequent calculus for classical first-order logic. It is well known that this system, in its most general form, is neither confluent nor strongly normalizing. In this work we take a coarser (and mathematically more realistic) look at cut-free proofs. We analyze whic...

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Main Authors: Stefan Hetzl, Lutz Straßburger
Format: Article
Language:English
Published: Logical Methods in Computer Science e.V. 2013-12-01
Series:Logical Methods in Computer Science
Subjects:
Online Access:https://lmcs.episciences.org/727/pdf
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author Stefan Hetzl
Lutz Straßburger
author_facet Stefan Hetzl
Lutz Straßburger
author_sort Stefan Hetzl
collection DOAJ
description We consider cut-elimination in the sequent calculus for classical first-order logic. It is well known that this system, in its most general form, is neither confluent nor strongly normalizing. In this work we take a coarser (and mathematically more realistic) look at cut-free proofs. We analyze which witnesses they choose for which quantifiers, or in other words: we only consider the Herbrand-disjunction of a cut-free proof. Our main theorem is a confluence result for a natural class of proofs: all (possibly infinitely many) normal forms of the non-erasing reduction lead to the same Herbrand-disjunction.
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spelling doaj.art-4d39ecc186364a339c0563779d3af15b2024-03-08T09:30:37ZengLogical Methods in Computer Science e.V.Logical Methods in Computer Science1860-59742013-12-01Volume 9, Issue 410.2168/LMCS-9(4:24)2013727Herbrand-ConfluenceStefan Hetzlhttps://orcid.org/0000-0002-6461-5982Lutz StraßburgerWe consider cut-elimination in the sequent calculus for classical first-order logic. It is well known that this system, in its most general form, is neither confluent nor strongly normalizing. In this work we take a coarser (and mathematically more realistic) look at cut-free proofs. We analyze which witnesses they choose for which quantifiers, or in other words: we only consider the Herbrand-disjunction of a cut-free proof. Our main theorem is a confluence result for a natural class of proofs: all (possibly infinitely many) normal forms of the non-erasing reduction lead to the same Herbrand-disjunction.https://lmcs.episciences.org/727/pdfcomputer science - logic in computer science
spellingShingle Stefan Hetzl
Lutz Straßburger
Herbrand-Confluence
Logical Methods in Computer Science
computer science - logic in computer science
title Herbrand-Confluence
title_full Herbrand-Confluence
title_fullStr Herbrand-Confluence
title_full_unstemmed Herbrand-Confluence
title_short Herbrand-Confluence
title_sort herbrand confluence
topic computer science - logic in computer science
url https://lmcs.episciences.org/727/pdf
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AT lutzstraßburger herbrandconfluence