Definition t_struct_btree := Tstruct _btreeNode noattr.

Lemma In_sorted_range : forall d lo hi x l (Hsort : sorted l) (Hlo : 0 <= lo <= hi) (Hhi : hi <= Zlength l) (Hin : In x (sublist lo hi l)), Znth lo l d <= x <= Znth (hi - 1) l d.