proposition: Lemma mulRA x y z : x * (y * z) == x * y * z.
proof: Proof. exact: (Real.mul_associative R). Qed.
imports: mathcomp(ssreflect ssrfun ssrbool eqtype ssrnat div order) mathcomp(ssralg ssrnum ssrint rat intdiv) Coq(Morphisms Setoid) fourcolor(real realsyntax)