**Speaker:** David Denoncin (Paris)

**Title:** *Unitriangularity of the Decomposition Matrix of Finite Special
Unitary Groups*

**Abstract:**

In 2009 A. Kleshchev and P.H. Tiep proved, using algebraic methods, that the decomposition matrix of finite special linear groups is unitriangular in non-defining characteristic. We will explain, using geometrical tools first developed by G. Lusztig and N. Kawanaka, how this result can be recovered and be proved simultaneously for finite special unitary groups.