proposition: Lemma in_refine_rect r p : refine_rect r p = r (halfg p).
proof: Proof. by case: r p => x0 x1 y0 y1 [x y] /=; rewrite !lez_divRL ?ltz_divLR ?mulz2. Qed.
imports: HB(structures) mathcomp(ssreflect ssrfun ssrbool eqtype ssrnat seq path) mathcomp(div choice order ssralg ssrnum ssrint intdiv) fourcolor(hypermap)