proposition: Lemma divRR x : x != 0 -> x / x == 1.
proof: Proof. move=> nzx; case: x^-1 / IFR_cases => _ [][_ ->] //. exact: (Real.mul_inverse_right R) nzx. Qed.
imports: mathcomp(ssreflect ssrfun ssrbool eqtype ssrnat div order) mathcomp(ssralg ssrnum ssrint rat intdiv) Coq(Morphisms Setoid) fourcolor(real realsyntax)