fact: Definition nontrivial_ring m (r : seq G) := (m < fcard face (diskF r)) && (m < fcard face (diskFC r)).
imports: mathcomp(ssreflect ssrfun ssrbool eqtype ssrnat seq choice) mathcomp(fintype path fingraph) fourcolor(hypermap geometry patch sew snip color chromogram) fourcolor(coloring kempe)