English

Lax comma categories of ordered sets

Category Theory 2023-11-13 v3 General Topology

Abstract

Let Ord\mathsf{Ord} be the category of (pre)ordered sets. Unlike Ord/X\mathsf{Ord}/X, whose behaviour is well-known, not much can be found in the literature about the lax comma 2-category Ord//X\mathsf{Ord} //X. In this paper we show that the forgetful functor Ord//XOrd\mathsf{Ord} //X\to \mathsf{Ord} is topological if and only if XX is complete. Moreover, under suitable hypothesis, Ord//X\mathsf{Ord} // X is complete and cartesian closed if and only if XX is. We end by analysing descent in this category. Namely, when XX is complete and cartesian closed, we show that, for a morphism in Ord//X\mathsf{Ord} //X, being pointwise effective for descent in Ord\mathsf{Ord} is sufficient, while being effective for descent in Ord\mathsf{Ord} is necessary, to be effective for descent in Ord//X\mathsf{Ord} //X.

Keywords

Cite

@article{arxiv.2212.13541,
  title  = {Lax comma categories of ordered sets},
  author = {Maria Manuel Clementino and Fernando Lucatelli Nunes},
  journal= {arXiv preprint arXiv:2212.13541},
  year   = {2023}
}

Comments

12 pages

R2 v1 2026-06-28T07:54:05.492Z