Geodesically convex energies and confinement of solutions for a multi-component system of nonlocal interaction equations

Abstract

We consider a system of $n$ nonlocal interaction evolution equations on ${\mathbb{R}}^d$ with a differentiable matrix-valued interaction potential $W$. Under suitable conditions on convexity, symmetry and growth of $W$, we prove $\lambda$-geodesic convexity for some $\lambda \in \mathbb{R}$ of the associated interaction energy with respect to a weighted compound distance of Wasserstein type. In particular, this implies existence and uniqueness of solutions to the evolution system. In one spatial dimension, we further analyse the qualitative properties of this solution in the non-uniformly convex case. We obtain, if the interaction potential is sufficiently convex far away from the origin, that the support of the solution is uniformly bounded. Under a suitable Lipschitz condition for the potential, we can exclude finite-time blow-up and give a partial characterization of the long-time behaviour.

arXiv comment19 pages, no figures. This research has been supported by the German Research Foundation (DFG), SFB TRR 109. v3: minor revision