Hint Rewrite wf_moves_cons wf_moves_append: pmov.
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 dtransition_preserves_wf_state:
forall st st',
dtransition st st' -> wf_state st -> wf_state st'.