We consider the structure  $({\Bbb Z}, + ,0,|_{p_1 } , \ldots ,|_{p_n } )$, where
$({\Bbb Z}, + ,0,|_{p_1 } , \ldots ,|_{p_n } )$, where  $x|_p y$ means
$x|_p y$ means  $v_p \left( x \right) \leqslant v_p \left( y \right)$ and vp is the p-adic valuation. We prove that this structure has quantifier elimination in a natural expansion of the language of abelian groups, and that it has dp-rank n. In addition, we prove that a first order structure with universe
$v_p \left( x \right) \leqslant v_p \left( y \right)$ and vp is the p-adic valuation. We prove that this structure has quantifier elimination in a natural expansion of the language of abelian groups, and that it has dp-rank n. In addition, we prove that a first order structure with universe  ${\Bbb Z}$ which is an expansion of
${\Bbb Z}$ which is an expansion of  $({\Bbb Z}, + ,0)$ and a reduct of
$({\Bbb Z}, + ,0)$ and a reduct of  $({\Bbb Z}, + ,0,|_p )$ must be interdefinable with one of them. We also give an alternative proof for Conant’s analogous result about
$({\Bbb Z}, + ,0,|_p )$ must be interdefinable with one of them. We also give an alternative proof for Conant’s analogous result about  $({\Bbb Z}, + ,0, < )$.
$({\Bbb Z}, + ,0, < )$.