English

Constructible hypersheaves via exit paths

Algebraic Topology 2021-02-25 v1

Abstract

The goal of this article is to extend a theorem of Lurie ShA(X)=Fun(ExitA(X),S) \mathsf{Sh}_A (X) = \mathsf{Fun}(\mathsf{Exit}_A (X), \mathsf{S}) representing constructible sheaves with values in S \mathsf{S} , the \infty -category of spaces, on a stratified space X X with poset of strata A A , as functors from the exit paths \infty -category ExitA(X) \mathsf{Exit}_A (X) to S \mathsf{S} . Lurie's representation theorem works provided A A satisfy the ascending chain condition. This typically rules out infinite dimensional examples of stratified space. Building on it and with the help of a stratified homotopy invariance theorem from Haine, we show that when X X is a nice enough A A -stratified space and when A A is itself stratified A0A1A A_{\leq 0} \subset A_{\leq 1} \subset \cdots \subset A by posets satisfying the ascending chain condition, HypA(X)=Fun(ExitA(X),S) \mathsf{Hyp}_A (X) = \mathsf{Fun}(\mathsf{Exit}_A(X), \mathsf{S}) the \infty -category of A A -constructible hypersheaves on X X is represented by functors from the exit paths \infty -category of X X . There are two types of nice stratified spaces on which this extended representation theorem applies: conically stratified spaces and spaces that are sequential colimits of conically stratified spaces. Examples of application include the metric and the topological exponentials of a Fr\'echet manifold, locally countable simplicial complexes and more generally, locally countable cylindrically normal CW-complexes.

Keywords

Cite

@article{arxiv.2102.12325,
  title  = {Constructible hypersheaves via exit paths},
  author = {Damien Lejay},
  journal= {arXiv preprint arXiv:2102.12325},
  year   = {2021}
}

Comments

30 pages

R2 v1 2026-06-23T23:28:32.534Z