Instance lt_compat : Proper (eq==>eq==>iff) lt.Instance lt_strorder : StrictOrder lt.Definition compare t1 t2 :=
    let ft1 := fstpp(t1) in
    let ft2 := fstpp(t2) in
    let st1 := sndpp(t1) in
    let st2 := sndpp(t2) in
    match (Pos.compare ft1 ft2) with
      | Lt => Lt
      | Eq => Pos.compare st1 st2
      | Gt => Gt
    end.

Lemma compare_spec : forall t1 t2, CompSpec eq lt t1 t2 (compare t1 t2).