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

Lemma break_strip:
forall f ve te m k,
star (CC.State f Sbreak k ve te m) (CC.State f Sbreak (strip_skip' k) ve te m).