Fibrations and Koszul duality in locally Cartesian localisations
Abstract
I show that any locally Cartesian left localisation of a presentable infinity-category admits a right proper model structure in which all morphisms are cofibrations, and obtain a Koszul duality classification of its fibrations. By a simple criterion in terms of generators for a localisation to be locally Cartesian, this applies to any nullification functor. In particular, it includes examples with non-trivial "homotopical content." I further describe, and provide examples from, the set of fibrations in three contexts: the higher categorical Thomason model structure of Mazel-Gee, where fibrations are local systems; Morel-Voevodsky A1-localisation, where they are a higher analogue of A1-covering spaces; and the Quillen plus construction, where they are related to loop space modules trivialised over the universal acyclic extension.
Cite
@article{arxiv.2105.12316,
title = {Fibrations and Koszul duality in locally Cartesian localisations},
author = {Andrew W. Macpherson},
journal= {arXiv preprint arXiv:2105.12316},
year = {2021}
}
Comments
20 pages. v2: Examples substantially expanded, added Koszul duality statements. The title of this paper was previously "Locally Cartesian localisations and the higher Thomason model structure." Keywords: model infinity category, right proper, nullification, A1 homotopy, plus construction, groupoid completion, Koszul duality