English

Topoi with enough points

Category Theory 2024-07-08 v2 Algebraic Geometry Logic

Abstract

We extend Deligne's original argument showing that locally coherent topoi have enough points, clarified using collage diagrams. We show that our refinement of Deligne's technique can be adapted to recover every existing result of this kind, including the most recent results about κ\kappa-coherent κ\kappa-topoi. Our presentation allows us to relax the cardinality assumptions typically imposed on the sites involved. We show that a larger class of locally finitely presentable toposes have enough points and that a closed subtopos of a topos with enough points has enough points.

Keywords

Cite

@article{arxiv.2403.15338,
  title  = {Topoi with enough points},
  author = {Ivan Di Liberti and Morgan Rogers},
  journal= {arXiv preprint arXiv:2403.15338},
  year   = {2024}
}

Comments

30 pages

R2 v1 2026-06-28T15:30:08.619Z