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The Undecidability of FO3 and the Calculus of Relations with Just One Binary Relation
Yoshiki Nakamura

The Undecidability of FO3 and the Calculus of Relations with Just One Binary Relation

Author / Organization:
Computer Science & Mathematics Published 2026 Verification Pending

Overview & Synopsis

The validity problem for first-order logic is a well-known undecidable problem. The undecidability also holds even for $\mathsf{FO}3$ and (equational formulas of) the calculus of relations. In this paper we tighten these undecidability results to the following: (1) $\mathsf{FO}3$ with just one binary relation is undecidable even without equality; and (2) the calculus of relations with just one character and with only composition, union, and complement is undecidable. Additionally we prove that the finite validity problem is also undecidable for the above two classes.

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Indexed from repository: arXiv (arxiv.org)
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Document Information

Document Title The Undecidability of FO3 and the Calculus of Relations with Just One Binary Relation
Author / Organization Yoshiki Nakamura
Subject & Discipline cs.LO
Categories Computer Science & Mathematics
Publication Year 2026
License / Rights arXiv Open Access / Creative Commons
Resource Verification Listed PDF (Verification Pending)
Original Host Website arXiv (arxiv.org)
File Format application/pdf (Portable Document Format)
Language EN
Catalog ID DOC-778
Original Source Link Visit Source Page on arxiv.org »