fact: Record plain_quasicubic : Prop := PlainQuasicubic { plain_quasicubic_is_plain :> plain; plain_quasicubic_is_quasicubic :> quasicubic }.
imports: mathcomp(ssreflect ssrfun ssrbool eqtype ssrnat seq choice) mathcomp(fintype path fingraph) fourcolor(hypermap jordan)