The exterior Steklov problem for Euclidean domains
Abstract
We investigate the Steklov eigenvalue problem in an exterior Euclidean domain. First, we present several formulations of this problem and establish the equivalences between them. Next, we examine various properties of the exterior Steklov eigenvalues and eigenfunctions. One of our main findings is an Escobar-type lower bound for the first exterior Steklov eigenvalue on convex domains in dimensions three and higher. This bound is expressed in terms of the principal curvatures of the boundary and is sharp, with equality attained for a ball. Moreover, it implies the existence of a sequence of convex domains with fixed volume and the first exterior Steklov eigenvalues tending to infinity. This contrasts with the interior case, as well as with the two-dimensional exterior case, for which we show that an analogue of the Weinstock isoperimetric inequality holds.
Cite
@article{arxiv.2511.09490,
title = {The exterior Steklov problem for Euclidean domains},
author = {Lukas Bundrock and Alexandre Girouard and Denis S. Grebenkov and Michael Levitin and Iosif Polterovich},
journal= {arXiv preprint arXiv:2511.09490},
year = {2025}
}
Comments
v2: minor revisions; 62 pages; 9 figures; 1 table