English

On the B\'enabou-Roubaud theorem

Category Theory 2025-04-18 v2

Abstract

We give a detailed proof of the B\'enabou-Roubaud theorem. As a byproduct it yields a weakening of its hypotheses: the base category does not need fibre products and the Beck-Chevalley condition, in the form of a natural transformation, can be weakened by only requiring the latter to be epi.

Cite

@article{arxiv.2404.00868,
  title  = {On the B\'enabou-Roubaud theorem},
  author = {Bruno Kahn},
  journal= {arXiv preprint arXiv:2404.00868},
  year   = {2025}
}

Comments

Final version, to appear in Cahiers de topologie et g\'eom\'etrie diff\'erentielle cat\'egoriques

R2 v1 2026-06-28T15:39:52.239Z