Fact sublist_refl : forall l, sublist l l.
Fact good_sublist : forall l l', sublist l l' -> good embeds l -> good embeds l'.
Fact bad_sublist :  forall l l', sublist l' l -> bad embeds l -> bad embeds l'.
Fact greater_add_letter : forall a w ws, greater embeds w ws ->
greater embeds (a :: w) ws.
Fact greater_remove_letter : forall a w ws,
greater embeds w ws -> greater embeds (a :: w) ws.
Fact sorted_remove_head : forall a l, sorted leA (a::l) -> sorted leA l.

Lemma good_merge : forall vs, good embeds vs ->
forall l, sorted leA l -> good embeds (merge_label vs l).