(** *Diagrams for machine steps*)

Lemma strong_tree_leq_map:
forall {A B} f1 f2 t (leq: option B -> option A -> Prop),
(forall a p, leq (Some (f1 p a)) (Some (f2 p a))) ->
leq None None ->
bounded_maps.strong_tree_leq
(@PTree.map A B f1 t)
(@PTree.map A A f2 t)
leq.