fact: Definition Kempe_closed (P : colseq -> Prop) := forall et, P et -> [/\ forall g, P (permt g et) & exists2 w, matchg [::] et w & forall et', matchg [::] et' w -> P et'].
imports: HB(structures) mathcomp(ssreflect ssrfun ssrbool eqtype ssrnat seq choice) mathcomp(fintype) fourcolor(color)