English

Colimits in the $\infty$-category of $\infty$-topoi and \'etale morphisms

Category Theory 2025-06-13 v1 Algebraic Topology

Abstract

We provide an alternative proof of Lurie's result that the wide subcategory of the \infty-category of \infty-topoi spanned by the \'etale morphisms is closed under small colimits. Our proof is based on a new characterization of \'etale morphisms of \infty-topoi in relation to univalent families and does not rely on a larger universe. During the proof, we also give an elementary construction of univalent completion.

Keywords

Cite

@article{arxiv.2506.10431,
  title  = {Colimits in the $\infty$-category of $\infty$-topoi and \'etale morphisms},
  author = {Taichi Uemura},
  journal= {arXiv preprint arXiv:2506.10431},
  year   = {2025}
}