English

Filter Quotients and Non-Presentable $(\infty,1)$-Toposes

Category Theory 2021-04-15 v2

Abstract

We define filter quotients of (,1)(\infty,1)-categories and prove that filter quotients preserve the structure of an elementary (,1)(\infty,1)-topos and in particular lift the filter quotient of the underlying elementary topos. We then specialize to the case of filter products of (,1)(\infty,1)-categories and prove a characterization theorem for equivalences in a filter product. Then we use filter products to construct a large class of elementary (,1)(\infty,1)-toposes that are not Grothendieck (,1)(\infty,1)-toposes. Moreover, we give one detailed example for the interested reader who would like to see how we can construct such an (,1)(\infty,1)-category, but would prefer to avoid the technicalities regarding filters.

Keywords

Cite

@article{arxiv.2001.10088,
  title  = {Filter Quotients and Non-Presentable $(\infty,1)$-Toposes},
  author = {Nima Rasekh},
  journal= {arXiv preprint arXiv:2001.10088},
  year   = {2021}
}

Comments

33 Pages, Final version

R2 v1 2026-06-23T13:22:22.145Z