**Question:** What is known about algorithms for numerically computing/approximating the [Prokhorov distance][3] between two measures? Recall that the Prokhorov distance metrizes the topology of weak(-*) convergence of measures on separable metric spaces, and is defined as follows. > Let $\mu_1$, $\mu_2$ be finite measures on a metric space $(X,d)$. The Prokhorov distance $\rho$ between them is, > $$\rho(\mu_1,\mu_2):=\inf \left\{ \epsilon > 0 : \mu_1(A) \le \mu_2(A^\epsilon)+\epsilon~ \text{ for all } A \in \mathcal{B} \right\},$$ > where $\mathcal{B}$ is the Borel $\sigma$-algebra on $X$ and $A^\epsilon$ is the $\epsilon$-neighborhood of $A$. Has a constructive/algorithmic approach to the Prokhorov metric been studied in any contexts? How could one go about constructing numerical algorithms to compute it? **Note:** *[Per][1] asked [this nearly identical question][2] at math.stackexchange, where it got no answers even after having a bounty for a week. I'm reposting here with his/her permission.* [1]: https://math.stackexchange.com/users/44557/per [2]: https://math.stackexchange.com/questions/224951/algorithms-for-computing-or-numerically-approximating-the-prokhorov-metric [3]: http://en.wikipedia.org/wiki/L%C3%A9vy%E2%80%93Prokhorov_metric