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 exec_skips: forall {s0 k s k'} (H1: match_cont (Kseq s0 :: k) (strip_skip' (CC.Kseq s k'))) f ve te m, match s0 with Sskip => False | Scontinue => False | Sloop _ _ => False | Sifthenelse _ _ _ => False | Sreturn _ => False | _ => True end -> exists k2, strip_skip' (CC.Kseq s k') = CC.Kseq s0 k2 /\ star (CC.State f s k' ve te m) (CC.State f s0 k2 ve te m).