  We examine the various properties of the three four-qubit monogamy relations,
all of which introduce the power factors in the three-way entanglement to
reduce the tripartite contributions. On the analytic ground as much as possible
we try to find the minimal power factors, which make the monogamy relations
hold if the power factors are larger than the minimal powers. Motivated to the
three-qubit monogamy inequality we also examine whether those four-qubit
monogamy relations provide the SLOCC-invariant four-way entanglement measures
or not. Our analysis indicate that this is impossible provided that the
monogamy inequalities are derived merely by introducing weighting power
factors.
