proposition: Lemma approx_scale s m : approx s (scale s m) m.
proof: Proof. by rewrite /approx /scale (mulRC m) mulRCA pmulKR //; apply: range1zz. Qed.
imports: mathcomp(ssreflect ssrfun ssrbool eqtype ssrnat seq choice) mathcomp(fintype tuple path fingraph bigop order ssralg) mathcomp(ssrnum ssrint div intdiv) fourcolor(hypermap geometry coloring grid matte) fourcolor(real realplane) Coq(Setoid Morphisms) fourcolor(realsyntax realprop)