The multiplicative eigenvalue problem and deformed quantum cohomology

Abstract

We construct deformations of the small quantum cohomology rings of homogeneous spaces G/P, and obtain an irredundant set of inequalities determining the multiplicative eigenvalue problem for the compact form K of G.

39 pages. We note that an equivalent form of one of our main theorems (Theorem 1.2) has been established independently by Nicolas Ressayre in arXiv:1310.7331 "On the quantum Horn problem"