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arXiv · 2609.10115

Littlewood subordination for de Branges--Rovnyak spaces

Emmanuel Fricain·Andreas Hartmann·William T. Ross·Dan Timotin
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Abstract

In this paper, we study composition operators that act between different de Branges-Rovnyak spaces. Our main results are suggested by a paper of Mashreghi and Shabankhah concerning composition operators between model spaces. We also answer several related open questions posed by Dellepiane and Seco. To prove these results, we apply reproducing kernel Hilbert space methods, Sarason's approach to composition operators as integral operators, and Aleksandrov-Clark measures.

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Emmanuel Fricain, Andreas Hartmann, William T. Ross, Dan Timotin. 2026-09-09. Littlewood subordination for de Branges--Rovnyak spaces. https://arxiv.org/abs/2609.10115

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