The Plackett family #
Aggregator: construction, cross-product ratio, symmetry and Blomqvist's beta (Basic),
concordance ordering and Fréchet–Hoeffding limits (Order), Spearman's rho (Spearman),
tail independence λ_L = λ_U = 0 (Tail), Kendall's tau as a double integral of the partial
derivatives and of a rational function (Kendall) and as a one-dimensional arctangent integral
(KendallArctan), full support and strict monotonicity, sign and limits of tau and rho
(KendallOrder).