Hello,

I've recently write down some measure for sets and now I wonder how it is called or where it is described?

The measure itself is the following: Let $A$ & $B$ -- two sets of values from a single space (real line for example) Let:

$d(A, B) = \sum_{a \in A} \sum_{b \in B} \frac{dist(a, b)}{len(A) * len(B)}$

- $dist(a, b)$ is the distance between two values
- $len(A)$ is the number of the elements in $A$

So, the measure itself is:

$|| A, B || = \frac{d^2(A, B)}{|d(A, A) d(B, B)|} - 1$