License: Creative Commons Attribution 4.0 International license (CC BY 4.0)
When quoting this document, please refer to the following
DOI: 10.4230/LIPIcs.ITP.2022.19
URN: urn:nbn:de:0030-drops-167280
Go to the corresponding LIPIcs Volume Portal

Hostert, Johannes ; Dudenhefner, Andrej ; Kirst, Dominik

Undecidability of Dyadic First-Order Logic in Coq

LIPIcs-ITP-2022-19.pdf (0.8 MB)


We develop and mechanize compact proofs of the undecidability of various problems for dyadic first-order logic over a small logical fragment. In this fragment, formulas are restricted to only a single binary relation, and a minimal set of logical connectives. We show that validity, satisfiability, and provability, along with finite satisfiability and finite validity are undecidable, by directly reducing from a suitable binary variant of Diophantine constraints satisfiability. Our results improve upon existing work in two ways: First, the reductions are direct and significantly more compact than existing ones. Secondly, the undecidability of the small logic fragment of dyadic first-order logic was not mechanized before. We contribute our mechanization to the Coq Library of Undecidability Proofs, utilizing its synthetic approach to computability theory.

BibTeX - Entry

  author =	{Hostert, Johannes and Dudenhefner, Andrej and Kirst, Dominik},
  title =	{{Undecidability of Dyadic First-Order Logic in Coq}},
  booktitle =	{13th International Conference on Interactive Theorem Proving (ITP 2022)},
  pages =	{19:1--19:19},
  series =	{Leibniz International Proceedings in Informatics (LIPIcs)},
  ISBN =	{978-3-95977-252-5},
  ISSN =	{1868-8969},
  year =	{2022},
  volume =	{237},
  editor =	{Andronick, June and de Moura, Leonardo},
  publisher =	{Schloss Dagstuhl -- Leibniz-Zentrum f{\"u}r Informatik},
  address =	{Dagstuhl, Germany},
  URL =		{},
  URN =		{urn:nbn:de:0030-drops-167280},
  doi =		{10.4230/LIPIcs.ITP.2022.19},
  annote =	{Keywords: undecidability, synthetic computability, first-order logic, Coq}

Keywords: undecidability, synthetic computability, first-order logic, Coq
Collection: 13th International Conference on Interactive Theorem Proving (ITP 2022)
Issue Date: 2022
Date of publication: 03.08.2022
Supplementary Material:

DROPS-Home | Fulltext Search | Imprint | Privacy Published by LZI