  We derive N-particle Bell-type inequalities under the assumption of partial
separability, i.e. that the N-particle system is composed of subsystems which
may be correlated in any way (e.g. entangled) but which are uncorrelated with
respect to each other. These inequalities provide, upon violation,
experimentally accessible sufficient conditions for full N-particle
entanglement, i.e. for N-particle entanglement that cannot be reduced to
mixtures of states in which a smaller number of particles are entangled. The
inequalities are shown to be maximally violated by the N-particle
Greenberger-Horne-Zeilinger (GHZ) states.
