Objects from the Class
Objects can be created by calls of the form new("archmCopula",
...) or by function "archmCopula". Implemented families are
Clayton, Gumbel, Frank, and Ali-Mikhail-Haq.Extends
Class "archmCopula" extends class "copula" directly.
Class "claytonCopula", "frankCopula",
"gumbelCopula" and "amhCopula" extends class
"archmCopula" directly.