  I explore the entanglement dynamics of a three qubit system in an initial
X-state undergoing decoherence including the possible exhibition of
entanglement sudden death (ESD). To quantify entanglement I utilize negativity
measures and make use of appropriate entanglement witnesses. The negativity
results are then extended to X-states with an arbitraty number of qubits. I
also demonstrate non-standard behavior of the tri-partite negativity
entanglement metric, its sudden appearance after some amount of decoherence
followed quickly by its disappearance. Finally, I solve for a lower bound on
the three qubit X-state concurrence, demonstrate when this bound goes to zero,
and outline simplifcations for the calculation of higher order X-state
concurrences.
