(** Some properties of [is_mill] and [dests_disjoint]. *)

Definition dests_disjoint (m1 m2: moves) : Prop :=
  list_disjoint (dests m1) (dests m2).

Lemma move_no_temp_append: forall m1 m2, move_no_temp m1 -> move_no_temp m2 -> move_no_temp (m1 ++ m2).