fact: Definition mr_proper n (mr : map_repr n) := forall i, cover m0 (mr i) /\ (forall j, m0 (mr i) (mr j) -> i = j).
imports: mathcomp(ssreflect ssrfun ssrbool eqtype ssrnat seq choice) mathcomp(fintype path fingraph bigop ssralg ssrnum ssrint) mathcomp(div intdiv) fourcolor(hypermap geometry coloring grid matte gridmap) fourcolor(real realplane realprop approx)