Faber series for $L^2$ holomorphic one-forms on Riemann surfaces with boundary (2303.15677v1)

Abstract: Consider a compact surface $\mathscr{R}$ with distinguished points $z_1,\ldots,z_n$ and conformal maps $f_k$ from the unit disk into non-overlapping quasidisks on $\mathscr{R}$ taking $0$ to $z_k$. Let $\Sigma$ be the Riemann surface obtained by removing the closures of the images of $f_k$ from $\mathscr{R}$. We define forms which are meromorphic on $\mathscr{R}$ with poles only at $z_1,\ldots,z_n$, which we call Faber-Tietz forms. These are analogous to Faber polynomials in the sphere. We show that any $L^2$ holomorphic one-form on $\Sigma$ is uniquely expressible as a series of Faber-Tietz forms. This series converges both in $L^2(\Sigma)$ and uniformly on compact subsets of $\Sigma$.