proposition: Lemma porbit_tpermD x y z : x != z -> y != z -> porbit (tperm x y) z = [set z].
proof: Proof. by move=> xz yz; apply/eqP; rewrite -porbit_fix tpermD. 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