proposition: Lemma _paco_convert4: forall T0 T1 T2 T3 (paco4: forall (y0: @T0) (y1: @T1 y0) (y2: @T2 y0 y1) (y3: @T3 y0 y1 y2) , Prop) y0 y1 y2 y3 (CONVERT: forall (x0: @T0) (x1: @T1 x0) (x2: @T2 x0 x1) (x3: @T3 x0 x1 x2) (EQ: _paco_id (@exist4T T0 T1 T2 T3 x0 x1 x2 x3 = @exist4T T0 T1 T2 T3 y0 y1 y2 y3)) , @paco4 x0 x1 x2 x3), @paco4 y0 y1 y2 y3.
proof: Proof. intros. apply CONVERT; reflexivity. Qed.