Published online by Cambridge University Press: 05 March 2021
Let $\Sigma $ be a compact surface with boundary. For a given conformal class c on
$\Sigma $ the functional
$\sigma _k^*(\Sigma ,c)$ is defined as the supremum of the kth normalized Steklov eigenvalue over all metrics in c. We consider the behavior of this functional on the moduli space of conformal classes on
$\Sigma $. A precise formula for the limit of
$\sigma _k^*(\Sigma ,c_n)$ when the sequence
$\{c_n\}$ degenerates is obtained. We apply this formula to the study of natural analogs of the Friedlander–Nadirashvili invariants of closed manifolds defined as
$\inf _{c}\sigma _k^*(\Sigma ,c)$, where the infimum is taken over all conformal classes c on
$\Sigma $. We show that these quantities are equal to
$2\pi k$ for any surface with boundary. As an application of our techniques we obtain new estimates on the kth normalized Steklov eigenvalue of a nonorientable surface in terms of its genus and the number of boundary components.
This work is supported by the Ministry of Science and Higher Education of the Russian Federation: agreement no. 075-03-2020-223/3 (FSSF-2020-0018).