  Reliable estimates of neutrino-nucleus reactions in the resonance-excitation
region play an important role in many of the on-going and planned neutrino
oscillation experiments. We study here neutrino-nucleus reactions in the
delta-particle excitation region with the use of neutrino pion-production
amplitudes calculated in a formalism in which the resonance contributions and
the background amplitudes are treated on the same footing. Our approach leads
to the neutrino-nucleus reaction cross sections that are significantly
different from those obtained in the conventional approach wherein only the
pure resonance amplitudes are taken into account. To assess the reliability of
our formalism, we calculate the electron-nucleus scattering cross sections in
the same theoretical framework; the calculated cross sections agree reasonably
well with the existing data.
