Copulas can be traced back to 1959, when Sklar first defined the term and some fundamental properties. Sklar’s theorem
shows that a multivariate distributed can be decomposed into two parts, a univariate marginal distribution of each variable
and a copula function that describes the relation between the variables. The formulation of Sklar’s theoremcan be described
as:
Let F be an n-dimensional distribution function with marginals F1, . . . , Fn. Then, there exists an n-copula C such that for
all x in Rn,