## Global equivariant homotopy theory, II

Principal Investigator

Prof. Dr. S. Schwede (Bonn)

## Project description

This project proposal is concerned with several basic questions about global equivariant homotopy theory, where the adjective `global' refers to simultaneous and compatible actions of all compact Lie groups. The framework is the model for global stable homotopy theory based on the category of orthogonal spectra, using a finer notion of equivalence than is usually considered, namely the global equivalences. The basic underlying observation is that every orthogonal spectrum gives rise to an orthogonal $G$-spectrum for every compact Lie group $G$, and the fact that all these individual equivariant objects come from one orthogonal spectrum implicitly encodes strong compatibility conditions as the group G varies. Prominent examples of global theories that can be modeled in this framework are equivariant stable homotopy, equivariant $K$-theory or equivariant bordism.

This project is a continuation of a project from the first funding period of the SPP 1786; specific aims in the second funding period are to develop and study:
- A global deloop of explicit Brauer induction
- Global localizations and the multifold ways of inverting the Bott class
- Realizing algebraic structure by ultra-commutative multiplications

## Related publications

### Published articles

Stefan Schwede, Global homotopy theory New Mathematical Monographs 34. Cambridge University Press, Cambridge, 2018. xvi+828 pp. www.cambridge.org/9781108425810.

Christian Wimmer, Rational extensions of the representation ring global functor and a splitting of global equivariant $K$-theory, Bulletin of the London Mathematical Society 50 (2018), 863-873 doi.org/10.1112/blms.12189

Markus Hausmann, Symmetric products and subgroup lattices, Geometry & Topology 22 (2018), no. 3, 1547–1591.

Stefan Schwede, Equivariant properties of symmetric products, Journal of the American Mathematical Society 30 (2017), 673-711.

Stefan Schwede, Orbispaces, orthogonal spaces, and the universal compact Lie group, to appear in Mathematische Zeitschrift arXiv:1711.06019

Markus Hausmann, Symmetric spectra model global homotopy theory of finite groups, Algebr. Geom. Topol. 19 (2019), no. 3, 1413–1452. doi.org/10.2140/agt.2019.19.1413

Stefan Schwede, Categories and orbispaces, to appear in Algebraic & Geometric Topology. arXiv:1810.06632

Markus Hausmann, Dominik Ostermayr, Filtrations of global equivariant K-theory, to appear in Mathematische Zeitschrift doi.org/10.1007/s00209-019-02338-1

### Preprints

Christian Wimmer, Rational global homotopy theory and geometric fixed points. PhD thesis, Universität Bonn, 2017