English

Automating proof search when equality is a logical connective

Logic in Computer Science 2026-05-20 v1

Abstract

Treating syntactic equality as a logical connective -- governed by left- and right-introduction rules within the sequent calculus -- offers an elegant and powerful approach to term identity. This treatment of equality allows for the derivation of core mathematical principles, such as Peano's axioms (excluding induction), and serves as a foundation for the Abella interactive proof assistant. However, integrating this equality into automated proof search remains challenging. We present a proof search procedure that extends unification to handle the complexities of quantifier alternation and equations that occur in both positive and negative occurrences. While established logical frameworks such as λ\lambdaProlog and LF lack direct support for this kind of equality, our procedure enables a lightweight logical framework that addresses this gap. Our system enables unification-aware proof search across a diverse range of first-order sequent calculi that can directly use this form of equality.

Keywords

Cite

@article{arxiv.2605.20054,
  title  = {Automating proof search when equality is a logical connective},
  author = {Kaustuv Chaudhuri and Arunava Gantait and Dale Miller},
  journal= {arXiv preprint arXiv:2605.20054},
  year   = {2026}
}

Comments

To appear in IJCAR 2026: International Joint Conference on Automated Reasoning, Lisbon (Portugal), July 2026