Hint Rewrite is_mill_cons is_mill_append
dests_disjoint_cons_left dests_disjoint_cons_right
dests_disjoint_append_left dests_disjoint_append_right
notin_dests_cons notin_dests_append: pmov.
(** ** Transitions preserve well-formedness *)

Lemma transition_preserves_wf:
forall st st',
transition st st' -> state_wf st -> state_wf st'.