English

Global Picard Spectra and Borel Parametrized Algebra

Algebraic Topology 2025-03-07 v1 Category Theory

Abstract

We answer a question of Schwede on the existence of global Picard spectra associated to his ultra-commutative global ring spectra; given an ultra-commutative global ring spectrum RR, we show there exists a global spectrum piceq(R)\mathrm{pic}_\mathrm{eq}(R) assembling the Picard spectra of all underlying GG-equivariant ring spectra resGR\mathrm{res}_G R of RR into one object, in that for all finite groups GG, the genuine fixed points are given by piceq(R)Gpic(ModresGR(SpG))\mathrm{pic}_\mathrm{eq}(R)^G \simeq \mathrm{pic}(\mathrm{Mod}_{\mathrm{res}_G R}(\mathrm{Sp}_G)). Along the way, we develop a generalization of Borel-equivariant objects in the setting of parametrized higher algebra. We use this to assemble the symmetric monoidal categories of GG-spectra for all finite groups GG together with all restrictions and norms into a single `normed global category', and build a comparison functor which allows us to import ultra-commutative GG-equivariant or global ring spectra into the setting of parametrized higher algebra.

Keywords

Cite

@article{arxiv.2503.04456,
  title  = {Global Picard Spectra and Borel Parametrized Algebra},
  author = {Phil Pützstück},
  journal= {arXiv preprint arXiv:2503.04456},
  year   = {2025}
}

Comments

65 pages

R2 v1 2026-06-28T22:09:15.062Z