proposition: Lemma porbit_tpermR x y : porbit (tperm x y) y = [set x; y].
proof: Proof. by rewrite tpermC porbit_tpermL; apply/setP => t; rewrite !in_set2 orbC. 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