# Orientations of ring spectra

String orientations on KO and TMF

Yuqing Shi and I are organising a reading seminar on orientations of structured ring spectra. The goal will be to understand the construction of the Spin and String orientations on real K-theory $\mathrm{KO}$, and the String orientation on topological modular forms $\mathrm{tmf}$. We (usually) meet on Tuesdays, from 13:30 to 15:30; any deviations are indicated in the schedule below. Note that the location changes a couple of times.

We have prepared a list of abstracts for the talks.

## Schedule

• March 1, 13:30-15:30, in Minnaert 0.16.
1. Introduction, Lennart Meier.

• March 8, 13:30-15:30, in Minnaert 0.16.
2. Prerequisites, Miguel Barrero.

• March 15, 13:30-15:30, in Minnaert 0.16.
3. Thom spectra, Max Blans.

• March 22, 13:30-15:30, in Minnaert 0.16.
4. The $\widehat{A}$-genus, Yuqing Shi.

• March 29, 13:30-15:30, in Minnaert 0.16.
5. The Atiyah–Bott–Shapiro orientation as a map of spectra, Miguel Barata.

• April 5, 13:30-15:30, in HFG 610.
6. Elliptic curves and elliptic genera, Sven van Nigtevecht.

• April 12, 13:30-15:30, in BBG 161.
7. Calculations with elliptic genera and properties.

• April 19, 13:30-15:30, in BBG 161.
8. Introduction to $\mathrm{TMF}$, Jack Davies.

• April 26, 13:30-15:30, in BBG 161.
9. Introduction to the Witten genus, Luuk Stehouwer.

• May 3, 13:30-15:30, in BBG 161.
10. $\mathrm{TMF}$ and String bordism.