English

A synthetic construction of universal cocartesian fibrations

Category Theory 2026-03-31 v1 Algebraic Topology

Abstract

We give a model-independent construction of directed univalent cocartesian fibrations of (,1)(\infty,1)-categories, and prove a straightening equivalence against such fibrations. The key step is showing that cocartesian fibrations descend along localisations, which we accomplish by analysing mapping spaces of localisations. Along the way we introduce a directed version of the join construction, giving a sequential colimit description of the full image of any functor.

Keywords

Cite

@article{arxiv.2603.28688,
  title  = {A synthetic construction of universal cocartesian fibrations},
  author = {Christian Sattler and David Wärn},
  journal= {arXiv preprint arXiv:2603.28688},
  year   = {2026}
}

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31 pages