Ltac jump_simpl :=
  repeat
    match goal with
      | |- context [jump xH] => rewrite (jump_simpl xH)
      | |- context [jump (xO ?p)] => rewrite (jump_simpl (xO p))
      | |- context [jump (xI ?p)] => rewrite (jump_simpl (xI p))
    end.

Lemma jump_succ j l x : jump (Pos.succ j) l x = jump 1 (jump j l) x.