English

A counterexample in quasi-category theory

Algebraic Topology 2019-10-22 v3 Category Theory

Abstract

We give an example of a morphism of simplicial sets which is a monomorphism, bijective on 0-simplices, and a weak categorical equivalence, but which is not inner anodyne. This answers an open question of Joyal. Furthermore, we use this morphism to refute a plausible description of the class of fibrations in Joyal's model structure for quasi-categories.

Keywords

Cite

@article{arxiv.1904.04965,
  title  = {A counterexample in quasi-category theory},
  author = {Alexander Campbell},
  journal= {arXiv preprint arXiv:1904.04965},
  year   = {2019}
}

Comments

3 pages; to appear in Proceedings of the AMS

R2 v1 2026-06-23T08:34:54.445Z