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_cont_strip: forall s k k', match_cont (strip_skip k) (strip_skip' k') -> match_cont (strip_skip (Kseq s :: k)) (strip_skip' (CC.Kseq s k')).