Minc's permanent upper-bound conjecture

Let $M$ be an $n\times n$ matrix with entries in $\{0,1\}$ and row sums $d_1,\dotsc,d_n$. Minc's conjecture. The permanent of $M$ is at most

$$\prod_{i=1}^n (d_i!)^{1/d_i}.$$

Minc's conjecture was proved by Brégman and later given a shorter proof by Schrijver, so the conjecture is now a theorem.