  The effect of Holstein electron-phonon interaction on a Hubbard model close
to a Mott-Hubbard transition at half-filling is investigated by means of
Dynamical Mean-Field Theory. We observe a reduction of the effective mass that
we interpret in terms of a reduced effective repulsion. When the repulsion is
rescaled to take into account this effect, the quasiparticle low-energy
features are unaffected by the electron-phonon interaction. Phonon features are
only observed within the high-energy Hubbard bands. The lack of electron-phonon
fingerprints in the quasiparticle physics can be explained interpreting the
quasiparticle motion in terms of rare fast processes.
