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).