proposition: Lemma cycle_type_cyclic s : (s \is cyclic) = (count (fun x => x != 1) (cycle_type s) == 1).
proof: Proof. Proof using. by rewrite -card_pred_card_porbits /porbit_set. Qed.
imports: mathcomp.ssreflect.ssreflect mathcomp(ssrfun ssrbool eqtype ssrnat seq choice fintype) mathcomp(tuple finfun finset path bigop) mathcomp(fingroup perm action) mathcomp(ssralg matrix mxalgebra algC classfun) partition tools sorted permcomp fibered_set cycles