Shift invariant subspaces of large index in the Bloch space

Fuente: arXiv
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Autore principale: Biehler, Nikiforos
Natura: Preprint
Pubblicazione: 2024
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author Biehler, Nikiforos
author_facet Biehler, Nikiforos
contents We consider the shift operator $M_z$, defined on the Bloch space and the little Bloch space and we study the corresponding lattice of invariant subspaces. The index of a closed invariant subspace $E$ is defined as $\text{ind}(E) = \dim(E/M_z E)$. We construct closed, shift invariant subspaces in the Bloch space that can have index as large as the cardinality of the unit interval $[0,1]$. Next we focus on the little Bloch space, providing a construction of closed, shift invariant subspaces that have arbitrary large index. Finally we establish several results on the index for the weak-star topology of a Banach space and prove a stability theorem for the index when passing from (norm closed) invariant subspaces of a Banach space to their weak-star closure in its second dual. This is then applied to prove the existence of weak-star closed invariant subspaces of arbitrary index in the Bloch space.
format Preprint
id arxiv_https___arxiv_org_abs_2409_03562
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle Shift invariant subspaces of large index in the Bloch space
Biehler, Nikiforos
Functional Analysis
Complex Variables
30H30, 30B10, 47A15, 47B91
We consider the shift operator $M_z$, defined on the Bloch space and the little Bloch space and we study the corresponding lattice of invariant subspaces. The index of a closed invariant subspace $E$ is defined as $\text{ind}(E) = \dim(E/M_z E)$. We construct closed, shift invariant subspaces in the Bloch space that can have index as large as the cardinality of the unit interval $[0,1]$. Next we focus on the little Bloch space, providing a construction of closed, shift invariant subspaces that have arbitrary large index. Finally we establish several results on the index for the weak-star topology of a Banach space and prove a stability theorem for the index when passing from (norm closed) invariant subspaces of a Banach space to their weak-star closure in its second dual. This is then applied to prove the existence of weak-star closed invariant subspaces of arbitrary index in the Bloch space.
title Shift invariant subspaces of large index in the Bloch space
topic Functional Analysis
Complex Variables
30H30, 30B10, 47A15, 47B91
url https://arxiv.org/abs/2409.03562