  We discuss the possibility to interpret the residual entanglement for more
than three qubits in terms of distributed multipartite entanglement, or, in
other words, possible extensions of the Coffman-Kundu-Wootters monogamy
equality to higher qubit numbers. Existing knowledge on entanglement in
multipartite systems puts narrow constraints on the form of such extensions. We
study various examples for families of pure four-qubit states for which the
characterization of three-qubit and four-qubit entanglement in terms of
polynomial invariants is known. These examples indicate that, although families
with such extensions do exist, a generalized monogamy equality cannot be found
along those lines.
