Analytical characterization of the genuine multiparticle negativity
  The genuine multiparticle negativity is a measure of genuine multiparticle entanglement which can be computed numerically. We present several results how this entanglement measure can be characterized analytically. First, we show that with an appropriate normalization this measure can be seen as coming from a mixed convex roof construction. Based on this, we determine its value for $n$-qubit GHZ-diagonal states and four-qubit cluster-diagonal states. 
Martin Hofmann, Tobias Moroder and Otfried G\"uhne
quant-ph