English

First-order homotopical logic

Logic 2025-07-16 v2 Algebraic Topology Category Theory

Abstract

We introduce a homotopy-theoretic interpretation of intuitionistic first-order logic based on ideas from Homotopy Type Theory. We provide a categorical formulation of this interpretation using the framework of Grothendieck fibrations. We then use this formulation to prove the central property of this interpretation, namely homotopy invariance. To do this, we use the result from arXiv:1905.10690 that any Grothendieck fibration of the kind being considered can automatically be upgraded to a 2-dimensional fibration, after which the invariance property is reduced to an abstract theorem concerning pseudonatural transformations of morphisms into 2-dimensional fibrations.

Keywords

Cite

@article{arxiv.1908.08944,
  title  = {First-order homotopical logic},
  author = {Joseph Helfer},
  journal= {arXiv preprint arXiv:1908.08944},
  year   = {2025}
}

Comments

Major revision: added several sections, fixed an error in (what is now) Theorem 12.2, restructured, rewrote introduction and expository material, updated to reflect changes in arXiv:1905.10690. 54 pages, comments welcome!