  We consider the problem of determining whether genuine multipartite
entanglement was produced in an experiment, without relying on a
characterization of the systems observed or of the measurements performed. We
present an n-partite inequality that is satisfied by all correlations produced
by measurements on biseparable quantum states, but which can be violated by
n-partite entangled states, such as GHZ states. In contrast to traditional
entanglement witnesses, the violation of this inequality implies that the state
is not biseparable independently of the Hilbert space dimension and of the
measured operators. Violation of this inequality does not imply, however,
genuine multipartite non-locality. We show more generically how the problem of
identifying genuine tripartite entanglement in a device-independent way can be
addressed through semidefinite programming.
