abstract: I will present a unified point of view on fractional perimeters and Riesz potentials. Denoting by $Hs$ - for $s \in (0, 1)$ - the $s$-fractional perimeter and by $Js$ - for $s \in (-d, 0)$ - the $s$-Riesz energies acting on characteristic functions, I will show that the functionals $Hs$ and $Js$, up to a suitable additive renormalization diverging when $s \to 0$, belong to a continuous one-parameter family of functionals, which for $s = 0$ gives back a new object we refer to as $0$-fractional perimeter. All the convergence results are obtained in the framework of $\Gamma$-convergence. I will also discuss the convergence of the fractional mean curvature flow as $s\to 0$.
These results are in collaboration with A. Cesaroni, L. De Luca and M. Ponsiglione.