  In this paper, we consider the problem of how to quantify entanglement for
any multipartite quantum states. For bipartite pure states partial entropy is a
good entanglement measure. By using partial entropy, we firstly introduce the
Combinatorial Entropy of Fully entangled states (CEF) which can be used to
quantify entanglement for any fully entangled pure states. In order to quantify
entanglement for any multipartite states we also need another concept the
Entanglement Combination (EC) which can be used to completely describe the
entanglement between any parties of the given quantum states. Combining CEF
with EC, we define the Combinatorial Entropy (CE) for any multipartite pure
states and present some nice properties which indicate CE is a good
entanglement measure. Finally, we point out the feasibility of extending these
three concepts to mixed quantum states.
