English

Global homotopy theory via partially lax limits

Algebraic Topology 2025-06-17 v3 Category Theory

Abstract

We provide new \infty-categorical models for unstable and stable global homotopy theory. We use the notion of partially lax limits to formalize the idea that a global object is a collection of GG-objects, one for each compact Lie group GG, which are compatible with the restriction-inflation functors. More precisely, we show that the \infty-category of global spaces is equivalent to a partially lax limit of the functor sending a compact Lie group GG to the \infty-category of GG-spaces. We also prove the stable version of this result, showing that the \infty-category of global spectra is equivalent to the partially lax limit of a diagram of GG-spectra. Finally, the techniques employed in the previous cases allow us to describe the \infty-category of proper GG-spectra for a Lie group GG, as a limit of a diagram of HH-spectra for HH running over all compact subgroups of GG.

Keywords

Cite

@article{arxiv.2206.01556,
  title  = {Global homotopy theory via partially lax limits},
  author = {Sil Linskens and Denis Nardin and Luca Pol},
  journal= {arXiv preprint arXiv:2206.01556},
  year   = {2025}
}

Comments

70 pages. Improved introduction plus small reorganization of some results. Comments welcome!