Document Type
Article
Publication Date
1-2016
Originally Published In
Trans. Amer. Math. Soc. 368 (2016), 6293-6324
Abstract
A seminal result of Agler proves that the natural de Branges-Rovnyak kernel function associated to a bounded analytic function on the bidisk can be decomposed into two shift-invariant pieces. Agler's decomposition is non-constructive—a problem remedied by work of Ball-Sadosky-Vinnikov, which uses scattering systems to produce Agler decompositions through concrete Hilbert space geometry. This method, while constructive, so far has not revealed the rich structure shown to be present for special classes of functions--inner and rational inner functions. In this paper, we show that most of the important structure present in these special cases extends to general bounded analytic functions. We give characterizations of all Agler decompositions, we prove the existence of coisometric transfer function realizations with natural state spaces, and we characterize when Schur functions on the bidisk possess analytic extensions past the boundary in terms of associated Hilbert spaces.
ORCID
http://orcid.org/0000-0002-9484-2537
Recommended Citation
Bickel, Kelly and Knese, Greg, "Canonical Agler decompositions and transfer function realizations" (2016). Mathematics Faculty Publications. 26.
https://openscholarship.wustl.edu/math_facpubs/26
Comments
This is a final author manuscript version of article first published in Transactions of the American Mathematical Society in 368 (no. 9): 6293-6324, published by the American Mathematical Society. http://dx.doi.org/10.1090/tran/6542 © Copyright 2016 American Mathematical Society