proposition: Lemma mulIr0_rreg x : (forall y, y * x = 0 -> y = 0) -> rreg x.
proof: Proof. exact: (@mulrI0_lreg R^c). Qed.
imports: HB(structures) mathcomp(ssreflect ssrfun ssrbool eqtype ssrnat div seq) mathcomp(choice fintype finfun bigop prime binomial)