fact: Definition gchop_rect d := let: (Grect x0 x1 y0 y1, Gpoint x y) := (r, halfg d) in match oddgP d with | Gpoint00 => Grect x0 x1 (Num.max y0 y) y1 | Gpoint01 => Grect (Num.max x0 x) x1 y0 y1 | Gpoint10 => Grect x0 (Num.min x1 (x + 1)) y0 y1 | Gpoint11 => Grect x0 x1 y0 (Num.min y1 (y + 1)) end.
imports: HB(structures) mathcomp(ssreflect ssrfun ssrbool eqtype ssrnat seq path) mathcomp(div choice order ssralg ssrnum ssrint intdiv) fourcolor(hypermap)