Unitriangular Shape of Decomposition Matrices of Unipotent Blocks

Olivier Brunat, Olivier Dudas, Jay Taylor

We show that the decomposition matrix of unipotent $\ell$-blocks of a finite reductive group $\mathbf{G}({\mathbb{F}}_q)$ has a unitriangular shape, assuming $q$ is a power of a good…