Inductive plus: state -> state -> Prop :=
  | plus_left: forall s1 s2 s3,
      CCstep s1 s2 -> star s2 s3 -> plus s1 s3.Inductive plus: state -> state -> Prop :=
  | plus_left: forall s1 s2 s3,
      CCstep s1 s2 -> star s2 s3 -> plus s1 s3.

Lemma match_find_label_None: forall lbl s1 k0 k0', match_cont (strip_skip k0) (strip_skip' k0') -> find_label lbl s1 k0 = None -> CC.find_label lbl s1 k0' = None with match_find_ls_None: forall lbl ls k0 k0', match_cont (strip_skip k0) (strip_skip' k0') -> find_label_ls lbl ls k0 = None -> CC.find_label_ls lbl ls k0' = None.