proposition: Lemma mulIr_eq0 x y : rreg x -> (y * x == 0) = (y == 0).
proof: Proof. exact: (@mulrI_eq0 R^c). Qed.
imports: HB(structures) mathcomp(ssreflect ssrfun ssrbool eqtype ssrnat div seq) mathcomp(choice fintype finfun bigop prime binomial)