fact: Definition nat_of_qarity qa := match qa with | Qa5 => 5 | Qa6 => 6 | Qa7 => 7 | Qa8 => 8 | Qa9 => 9 | Qa10 => 10 | Qa11 => 11 end.
imports: mathcomp(ssreflect ssrfun ssrbool eqtype ssrnat seq choice) mathcomp(fintype path fingraph) fourcolor(hypermap geometry coloring)