Dyson (1962abc) conjectured that the constant term in the Laurent series product_(1<=i!=j<=n) (1 - x_i/x_j)^(a_i) is the multinomial coefficient ((a_1 + a_2 + ... + a_n)!)/(a_1 !a_2 !...a_n !), based on a problem in particle physics. The theorem is called Dyson's conjecture, and was proved by Wilson and independently by Gunson. A definitive proof was subsequently published by Good.

Dixon's theorem | Macdonald's constant-term conjecture | multinomial coefficient | q-multinomial coefficient