The second through fifth order L-moments are perhaps the most common in
analysis situations. These L-moments have particular constraints on
magnitudes and relation to each other. This function
evaluates and L-moment object whether: L-scale ($\lambda_2 > 0$),
($L-skew (\eqn{|\tau_3| < 1)},
L-kurtosis (\eqn{0.25(5\tau_3^2 - 1) \le \tau_4 < 1}), and
\eqn{|\tau_5| < 1}.$
are.lmom.valid(lmom)lmom{A L-moment object created by lmom.ub or pwm2lmom.}TRUE{L-moments are valid.}
FALSE{L-moments are not valid.}Hosking, J.R.M., 1990, L-moments---Analysis and estimation of
distributions using linear combinations of order statistics: Journal
of the Royal Statistical Society, Series B, vol. 52, p. 105-124.
Hosking, J.R.M. and Wallis, J.R., 1997, Regional frequency analysis---An
approach based on L-moments: Cambridge University Press.