proposition: Lemma _paco_pre9: forall T0 T1 T2 T3 T4 T5 T6 T7 T8 (gf: rel9 T0 T1 T2 T3 T4 T5 T6 T7 T8) x0 x1 x2 x3 x4 x5 x6 x7 x8 (X: let gf' := gf in gf' x0 x1 x2 x3 x4 x5 x6 x7 x8), gf x0 x1 x2 x3 x4 x5 x6 x7 x8.
proof: Proof. intros; apply X. Defined.