fact: Definition binomialz (n m : int) : int := match n,m with | Posz n1, Posz m1 => binomial_rec n1 m1 true true | Negz n1, Posz m1 => binomial_rec n1 m1 false true | Posz n1, Negz m1 => binomial_rec n1 m1 true false | Negz n1, Negz m1 => binomial_rec n1 m1 false false end.
imports: mathcomp(all_ssreflect all_algebra) tactics