General Monogamy Inequality for Bipartite Qubit Entanglement
  We consider multipartite states of qubits and prove that their bipartite quantum entanglement, as quantified by the concurrence, satisfies a monogamy inequality conjectured by Coffman, Kundu, and Wootters. We relate this monogamy inequality to the concept of frustration of correlations in quantum spin systems. 
Tobias J. Osborne and Frank Verstraete