Definition listempty (lp: adr*adr) : mpred :=
!! (fst lp = snd lp) && emp.
Definition listrep' (R: adr*adr -> mpred) (lp: adr*adr) : mpred :=
listcons' R lp || listempty lp.
Definition listrep : adr*adr -> mpred := HORec listrep'.
Definition lseg (e1 e2: adr) : mpred := listrep (e1,e2).

Lemma allp_andp1 {A}{NA: NatDed A}{B}: forall (any: B) (P: B -> A) Q,
allp P && Q = ALL x:B, P x && Q.