Module LBsegWandQFrame.
Definition lbseg (sh: share) (contents: list int) (x z: val) : mpred :=
ALL tcontents: list int, listboxrep sh tcontents z -* listboxrep sh (contents ++ tcontents) x.

Lemma lbseg_lbseg: forall sh (s1 s2: list int) (x y z: val),
lbseg sh s2 y z * lbseg sh s1 x y |-- lbseg sh (s1 ++ s2) x z.