Let $a=a_1,a_2,...,a_n$ and $b=b_1,b_2,...,b_n$ be two sequence of real numbers. Define

$$D(a,b) := \sum_{\{i,j\}}\sum_{\{k,l\}}{(|a_i-a_j||b_k-b_l|-|a_k-a_l||b_i-b_j|)^2} .$$

Does this parameter have a name? I just need some reference if there's any.