Hint Resolve treebox_rep_saturate_local: saturate_local.
Definition insert_inv (p0: val) (t0: tree val) (x: Z) (v: val): environ -> mpred :=
EX p: val, EX t: tree val,
PROP()
LOCAL(temp _p p; temp _x (Vint (Int.repr x));   temp _value v)
SEP(treebox_rep t p;  (treebox_rep (insert x v t) p -* treebox_rep (insert x v t0) p0)).

(* Lemma ramify_PPQQ {A: Type} {NA: NatDed A} {SA: SepLog A} {CA: ClassicalSep A}: forall P Q, P |-- P * (Q -* Q). *)
Lemma tree_rep_nullval: forall t,
tree_rep t nullval |-- !! (t = E).