Section Cycles.
(* Elementary properties of cycles and order, needed in perm.v.  *)
(* More advanced results on the structure of cyclic groups will  *)
(* be given in cyclic.v.                                         *)
Variable gT : finGroupType.
Implicit Types x y : gT.
Implicit Types G : {group gT}.

Lemma cycle2g x : #[x] = 2 -> <[x]> = [set 1; x].