Session 17. Functional Analysis: relations to Complex Analysis and PDE

Bases in spaces of analytic functions and applications

Vyacheslav Zakharyuta, Sabancı University, Turkey
Let \(\Omega \) be a Stein manifold. If \(D\) is an open subset of \(\Omega \), we denote by \(A\left( D\right) \) the locally convex space of all functions analytic in \(D\) with the topology of locally uniform convergence in \(D\). For an arbitrary set \(E\subset \Omega ,\) \(A\left( E\right) \) is a set of all analytic germs on \(E\) considered with the locally convex topology of the inductive limit: \[ A\left( E\right) = \textrm{limind}_{G\in \mathcal{O}\left( E\right) }A\left( G\right) , \] where \(\mathcal{O}\left( E\right) \) is the set of all open neighborhoods of \( E\). Our goal is to give a survey of results on Schauder bases in those spaces (especially, for the cases when \(E\) is an open or compact set in \(\Omega \) ). Main attention will be paid to the following topics: existence of bases in spaces \(A\left( E\right) \), their construction and structure, extendible bases; orthogonal, doubly orthogonal and interpolation bases, application to isomorphic classification of spaces of analytic functions; applications to approximation, interpolation and extension of analytic functions. The one-dimensional case is considered separately, since some results can be proved easier than their multivariate counterparts, the others have no many-dimensional analogs at all. This is due to some specific one-dimensional tools (like the fundamental algebra theorem, or the Grothendieck-Köthe-Silva duality, or the potential theory in \( \mathbb{R}^{2}=\mathbb{C}\)). For \(\dim \Omega \geq 2\) the pluripotential theory and functional analysis methods play main role. Some long standing open problems will be discussed.
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