**Special Topology Seminar**

Come join us Monday** February 12, 2018 at 4:30 pm in RM 520, Professor Andrew Blumberg (UT Austin) will be giving a special lecture about “Equivariant Commutative Ring Spectra”.**

**Abstract**

One of the central developments in algebraic topology in the last 30 years has been the study of the chromatic filtration on the stable homotopy category. The chromatic perspective relates the fine structure of the stable category to the algebraic geometry of formal groups. In particular, an important role in the story is played by an elliptic cohomology theory called topological modular forms (tmf).

Calculations with forms of tmf that incorporate information about level structures suggest that the framework of equivariant derived algebraic geometry would be extremely useful. To develop this framework, it is necessary to understand equivariant commutative ring spectra. This turns out to be a subtle problem; in this talk I will explain the situation and what the answers look like.

**Mathematics Hall, Room 520**

**Monday February 12, 2018** at 4:30 pm