  The quantification and classification of quantum entanglement is a very
important and still open question of quantum information theory. In this paper,
we describe an entanglement measure for multipartite pure states (the minimum
of Shannon's entropy of orthogonal measurements). This measure is additive,
monotone under LOCC, and coincides with the reduced von Neumann entropy on
bipartite states. A method for numerical calculation of this measure by genetic
algorithms is also presented. Moreover, the minimization of entropy technique
is extended to fermionic states.
