Speaker : Prof. Nan-Kuo Ho (National Tsing-Hua University) Kostant, Steinberg, and the Stokes matrices of the tt*-Toda equations 2018-03-01 (Thu) 15:00 - 16:00 Auditorium, 6 Floor, Institute of Mathematics (NTU Campus) We propose a Lie-theoretic definition of the tt*-Toda equations for any complex simple Lie algebra $\mathfrak{g}$, based on the concept of topological-antitopological fusion which was introduced by Cecotti and Vafa. Our main result concerns the Stokes data of a certain meromorphic connection, whose isomonodromic deformations are controlled by these equations. Exploiting a framework introduced by Boalch, we show that this data has a remarkable structure, which can be described using Kostant's theory of Cartan subalgebras in apposition and Steinberg's theory of conjugacy classes of regular elements. A by-product of this is a convenient visualization of the orbit structure of the roots under the action of a Coxeter element. As an application, we compute canonical Stokes data of certain solutions of the tt*-Toda equations in terms of their asymptotics. This is a joint work with Martin Guest.