Inductive wf_state: state -> Prop :=
  | wf_state_intro: forall mu sigma tau,
      wf_moves mu -> wf_moves sigma -> wf_moves tau ->
      wf_state (State mu sigma tau).Inductive wf_state: state -> Prop :=
  | wf_state_intro: forall mu sigma tau,
      wf_moves mu -> wf_moves sigma -> wf_moves tau ->
      wf_state (State mu sigma tau).

Lemma parmove_wf_moves: forall mu, wf_moves mu (parmove mu).