Studying equivariant structures using transfer systems and Rubin functors

Speaker: Danika Van Niel

Date: Tue, Sep 15, 2026

Location: PIMS, University of British Columbia

Subject: Mathematics

Class: Scientific

CRG: Diagram Categories in Homotopy Theory

Abstract:

Transfer systems are combinatorial objects that encode information about equivariant operations. More precisely, a transfer system encodes the transfers (or wrong-way maps) carried by algebras over certain equivariant operads. Thus, transfer systems allow us to use combinatorial tools to study equivariant homotopy theory. Compatible pairs of transfer systems, which are a pair of transfer systems satisfying certain conditions, correspond to multiplicative structures compatible with an underlying additive structure. In particular, compatible pairs are closely related to $N_\infty$-operads which encode commutative structures in equivariant homotopy theory.

In this talk we introduce transfer systems, compatible pairs, and discuss how Rubin functors significantly aid our study of said transfer systems and their pairs. The work discussed in this talk is from two separate projects, the first is joint with DeMark, Hill, Kamel, Niu, Stoeckl, and Yan, and the second is joint with Darnall, Klanderman, Lewis, Shibata, and Trimble.