The TMS are proud to present **two** talks in the coming week. In addition to our usual Monday night talk, given by Prof. Ray Goldstein, we will also be having a special event on Tuesday evening, given by Prof. Don Zagier of the Max Planck Institute for Mathematics (MPIM) in Bonn. They both promise to be fantastic events and, if nothing else, you will have the excuse to see TMS’s one and only Joshua Lam as many as two times a week. More details for these two events are as follows: **Monday 1st Feb 8.30pm in the Winstanley Lecture Theatre.**

Speaker: Prof. Ray Goldstein FRS (Schlumberger Professor of Complex Physical Systems, DAMTP)

Title: Upside down and inside out: the biomechanics of cell sheet folding

Abstract: Deformations of cell sheets are ubiquitous in early animal development, often arising from a complex and poorly understood interplay of cell shape changes, division, and migration. In this talk I will describe an approach to understanding such problems based on perhaps the simplest example of cell sheet folding: the “inversion” process of the algal genus Volvox, during which spherical embryos literally turn themselves inside out through a process hypothesized to arise from cell shape changes alone. Through a combination of light sheet microscopy and elasticity theory a quantitative understanding of this process is now emerging.

**Tuesday 2nd Feb in MR2, Centre for Mathematical Sciences (time TBC)**

Speaker: Prof. Don Zagier (MPIM, Bonn)

Title: Sums of squares and sums of cubes

Abstract to follow, but here is a biography to whet your mathematical appetite:

Prof. Zagier finished high school aged 13 and subsequently studied at MIT for three years, completing his bachelor’s and master’s degrees at the age of 16. He then received his Phd under Friedrich Hirzebruch aged 20 and was named professor when he was 24. He has been a scientific member of the MPIM in Bonn since its founding and has been one of its directors since 1995.

Prof. Zagier’s main area of work is in number theory, but he has also done extensive work in seemingly unrelated areas. In collaboration with Benedict Gross he proved the Gross-Zagier formula which played an instrumental role in the solution of the Class Number Problem. He has also done work relating modular forms to string theory and black holes. Together with his former doctoral student Maxim Kontsevich he introduced the notion of ‘periods’ in a paper which features, among other things, L-functions and motives. He is perhaps best known for his “one-sentence proof of Fermat’s two squares theorem”. He is the winner of both the Cole Prize and the Von Staudt Prize.

**TL;DR**:

There will be two talks next week, one by Prof. Ray Goldstein and one by Prof. Don Zagier. More details for the Tuesday talk will follow shortly.