fact: Record planar_bridgeless_plain_precubic : Prop := PlanarBridgelessPlainPrecubic { planar_bridgeless_plain_precubic_base :> planar_bridgeless_plain; planar_bridgeless_plain_precubic_is_precubic :> precubic }.
imports: mathcomp(ssreflect ssrfun ssrbool eqtype ssrnat seq choice) mathcomp(fintype path fingraph) fourcolor(hypermap jordan)