Declare Module Semax : SEMAX.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).

(* Specifications: *)
Lemma lseg_eq: forall a, lseg a a = emp.