# MQI

## Seminar

### Eigencones and Levi movability

Ressayre, N (Université Montpellier 2)
Tuesday 15 October 2013, 11:30-12:30

Seminar Room 1, Newton Institute

#### Abstract

Let $g_{\lambda\mu\nu}$ denote the Kronecker coefficient. It is a multiplicity in the decomposition of the tensor product of two irreducible representations of the symmeric group. The set of triples $(\lambda,\mu,\nu)$ of bounded length such that $g_{\lambda\mu\nu}$ is nonzero generate a closed convex polyhedral cone. In this talk, we will give a description of these cones and more generaly of branching cones.

Some branching cones have an interpretation in terms of eigenvalues of Hermitian matrices known as the addive Horn problem. We will also give an answer of the so called multiplicative Horn problem.

#### Video

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