20 mar 2019 -- 17:00 [open in google calendar]

Sala Seminari (Dipartimento di Matematica di Pisa)

**Abstract.**

We study the Wasserstein distance between two measures $\mu,\nu$ which are mutually singular. In particular, we are interested in minimization problems of the form
$$W(\mu,{\cal A})=\inf\big\{W(\mu,\nu)\ :\ \nu\in{\cal A}\big\}$$
where $\mu$ is a given probability and ${\cal A}$ is contained in the class $\mu^\perp$ of probabilities that are singular with respect to $\mu$. Several cases for ${\cal A}$ are considered; in particular, when ${\cal A}$ consists of $L^1$ densities bounded by a constant, the optimal solution is given by the characteristic function of a domain. Some regularity properties of these optimal domains are also studied. Some numerical simulations are included, as well as the double minimization problem
$$\min\big\{P(B)+kW(A,B)\ :\

A\cap B

=0,\

A

=

B

=1\big\},$$
where $k>0$ is a fixed constant, $P(A)$ is the perimeter of $A$, and both sets $A,B$ may vary.