proposition: Lemma undup_cycle_cons : undup (x :: p) = orbit x.
proof: Proof. by have [n {1}->] := fcycle_consEflatten; rewrite undup_flatten_nseq ?undup_id. Qed.
imports: mathcomp(ssreflect ssrbool ssrfun eqtype ssrnat) mathcomp(seq path fintype)