intuition.
eapply comp_spec_eq_trans.
eapply comp_spec_eq_symm.
eapply comp_spec_right_ident.
comp_skip.
eapply shuffle_RndPerm_spec.
eapply comp_spec_ret; intuition.
Qed.

(* Specifications: *)
Theorem RndPerm_In_support :
forall n ls,
In ls (getSupport (RndPerm n)) ->
Permutation (allNatsLt n) ls.