We show that uniqueness results of the kind those obtained for KdV and Schrödinger equations ([7], [28]), are not valid for the dispersion generalized-Benjamin-Ono equation in the weighted Sobolev spacesfor appropriated s and r.In particular, we obtain that the uniqueness result proved for the dispersion generalized-Benjamin-Ono equation ([13]), is not true for all pairs of solutions u 1 = 0 and u 2 = 0. To achieve these results we employ the techniques present in our recent work [6]. We also improve some Theorems established for the dispersion generalized-Benjamin-Ono equation and for the Benjamin-Ono equation ([13], [12]).