English

All $(\infty,1)$-toposes have strict univalent universes

Algebraic Topology 2019-04-30 v2 Category Theory

Abstract

We prove the conjecture that any Grothendieck (,1)(\infty,1)-topos can be presented by a Quillen model category that interprets homotopy type theory with strict univalent universes. Thus, homotopy type theory can be used as a formal language for reasoning internally to (,1)(\infty,1)-toposes, just as higher-order logic is used for 1-toposes. As part of the proof, we give a new, more explicit, characterization of the fibrations in injective model structures on presheaf categories. In particular, we show that they generalize the coflexible algebras of 2-monad theory.

Keywords

Cite

@article{arxiv.1904.07004,
  title  = {All $(\infty,1)$-toposes have strict univalent universes},
  author = {Michael Shulman},
  journal= {arXiv preprint arXiv:1904.07004},
  year   = {2019}
}

Comments

71 pages. v2: fixed some typos, added a few remarks

R2 v1 2026-06-23T08:39:42.893Z