Lower Bounds of Concurrence for Multipartite States
  We study the entanglement of multipartite quantum states. Some lower bounds of the multipartite concurrence are reviewed. We further present more effective lower bounds for detecting and qualifying entanglement, by establishing functional relations between the concurrence and the generalized partial transpositions of the multipartite systems. 
Xue-Na Zhu, Ming Li and Shao-Ming Fei
quant-ph