Entanglement monogamy relations of qubit systems
  We investigate the monogamy relations related to the concurrence and the entanglement of formation. General monogamy inequalities given by the {\alpha}th power of concurrence and entanglement of formation are presented for N-qubit states. The monogamy relation for entanglement of assistance is also established. Based on these general monogamy relations, the residual entanglement of concurrence and entanglement of formation are studied. Some relations among the residual entanglement, entanglement of assistance, and three tangle are also presented. 
Xuena Zhu and Shaoming Fei
quant-ph