proposition: Lemma BRprod_div_ea x y z: realp x -> realp y -> realp z -> y <> \0r -> x = y *r z -> z = x /r y.
proof: Proof. by move => xy yr zr h -> ; rewrite BRdiv_prod. Qed.
imports: mathcomp(ssreflect ssrfun ssrbool eqtype ssrnat)