Maximal rank subgroups and strong functoriality of the additive eigencone

Abstract

Let $G$ be a simple connected complex Lie group. The additive eigencone of $G$ is a polyhedral cone containing the set of solutions to the additive eigenvalue problem, a generalization of the Hermitian eigenvalue problem. The additive eigencone is functorial, and for certain subgroups satisfies a stronger functoriality property: the eigencone of the subgroup is determined by the inequalities of the larger eigencone. Belkale and Kumar first studied this property for subgroups invariant under a diagram automorphism of $G$. We study a new class of subgroups arising from centralizers of torus elements that have the strong eigencone functoriality property.

Corrected typos and improved exposition; 16 pages