  A general shell model formalism for the nonmesonic weak decay of the
hypernuclei has been developed.It involves a partial wave expansion of the
emitted nucleon waves,preserves naturally the antisymmetrization between the
escaping particles and the residual core, and contains as a particular case the
weak Lambda-core coupling formalism. The hypernuclei are grouped having in view
their A-1 cores, that is in those with even-even, even-odd and odd-odd cores.It
is shown that in all three cases the nuclear structure manifests itself
basically through Pauli Principle, and very simple expressions are derived for
the neutron and proton induced decays rates, which does not involve the
spectroscopic factors.
