proposition: Lemma lift_lift_fuse_successor: forall `{LiftLiftFuse T} t s wk, lift wk s (shift s t) = lift (S wk) s t.
proof: Proof. intros. replace (S wk) with (wk + 1) by omega. eapply lift_lift_fuse. omega. Qed.
imports: Dblib.DblibTactics