Compute the Fr<U+00E9>chet--Hoeffding lower bound copula (Nelsen, 2006, p. 11), which is defined as
$$\mathbf{W}(u,v) = \mathrm{max}(u+v-1,0)\mbox{.}$$
This is the copula of perfect anti-association (countermonotonicity, perfectly negative dependence) between \(U\) and \(V\) and is sometimes referred to as the countermonotonicity copula. Its opposite is the \(\mathbf{M}(u,v)\) copula (comonotonicity copula; M
), and statistical independence is the \(\mathbf{\Pi}(u,v)\) copula (P
).