Kostant's convexity theorem

Kostant's convexity theorem is a result in the field of representation theory and geometry, specifically relating to the representation of Lie groups and the geometry of their associated symmetric spaces. The theorem is named after Bertram Kostant, who made significant contributions to these areas. In essence, Kostant's convexity theorem states that for a compact Lie group \( G \) and a certain class of representations, the image of the highest weight map is a convex polytope in the weight space.