The Van der Waerden conjecture for mixed discriminants

We prove that the mixed discriminant of doubly stochastic n-tuples of semidefinite hermitian n×n matrices is bounded below by n!nn and that this bound is uniquely attained at the n-tuple (1nI,…,1nI). This result settles a conjecture posed by R. Bapat in 1989. We consider various generalizations and applications of this result.