| Title | Bergman spaces on disconnected domains |
| Authors | Alexandru Aleman, Stefan Richter, William T Ross |
| Publication | Canadian journal of mathematics / Journal Canadien de Mathematiques |
| Year | 1996 |
| Volume | 48 |
| Issue | 2 |
| Pages | 225 - 243 |
| Document type | Article |
| Status | Published |
| Quality controlled | Yes |
| Language | eng |
| Publisher | Canadian Mathematical Society |
| Abstract English | For a bounded open set $U$ in the complex plane, we consider the Bergman space $L^p_a(U)$ of $p$th-power area-integrable analytic functions on $U$, with $p$ assumed to be in the range $1\le p<+\infty$, where the lower bound assures that $L^p_a(U)$ is a Banach space. Fix a bounded domain $G$ and a compact subset $K$ of $G$ with zero area measure. Let $M$ be a closed subspace of $L^p_a(G\sbs K)$. We say that $M$ is invariant provided that $zf\in M$ whenever $f\in M$. Aleman, Richter, and Ross study those invariant subspaces $M$ of $L^p_a(G\sbs K)$ that contain $L^p_a(G)$. They also add the requirement that $M$ have index one, which is taken to mean that $(z-\lambda)M$ has codimension $1$ in $M$, for all $\lambda\in G\sbs K$. Natural examples of such invariant subspaces are those of the form $M=L^p_a(G\sbs E)$, where $E$ is a closed subset of $K$. The authors show that for $p<2$, these are indeed all such invariant subspaces which can be found. For $p\ge2$, this is not so, but nevertheless a complete classification can be found in terms of quasi-closed subsets $E$ of $K$. <br> <br> If the condition that the index of $M$ is one is dropped, then the structure of such invariant subspaces can be extremely complicated. If, however, $G\sbs K$ is connected, the authors show that $M$ automatically has index one (due to the assumption that $M$ should contain $L_a^p(G)$). |
| ISBN/ISSN/Other | ISSN: 0008414X |
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