2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/89083We show that universally covariant cloning is not optimal for achieving joint measurements of noncommuting observables with minimum added noise. For such a purpose a cloning transformation that is covariant with respect to a restricted transformation group is needed.4 pages. For "Quantum Communication, Measurement and Computing 3", O. Hirota and P. Tombesi, eds., Kluwer Acad./Plenum Publ., New YorkQuantum Physicstext