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Related papers: Invariant subspaces of perturbed backward shift

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We discuss relations between uniform minimality, unconditionality and interpolation for families of reproducing kernels in backward shift invariant subspaces. This class of spaces contains as prominent examples the Paley-Wiener spaces for…

Complex Variables · Mathematics 2009-01-23 Eric Amar , Andreas Hartmann

We extend the notion of anticoherent spin states to anticoherent subspaces. An anticoherent subspace of order t, is a subspace whose unit vectors are all anticoherent states of order t. We use Klein's description of algebras of polynomials…

Mathematical Physics · Physics 2017-06-28 Rajesh Pereira , Connor Paul-Paddock

In this paper we give two complete characterizations of the Poletsky- Stessin- Hardy spaces in the complex plane: First in terms of their boundary values as a weighted subclass of the usual $L^p$ class with respect to the arclength measure…

Complex Variables · Mathematics 2012-10-08 Nihat Gokhan Gogus , Muhammed Ali Alan

We study the behaviour on rearrangement-invariant spaces of such classical operators of interest in harmonic analysis as the Hardy-Littlewood maximal operator (including the fractional version), the Hilbert and Stieltjes transforms, and the…

Functional Analysis · Mathematics 2020-06-05 David E. Edmunds , Zdeněk Mihula , Vít Musil , Luboš Pick

This paper is a sequel to [6]. In that paper we transferred the discussions in [1] and [13] concerning almost invariant half-spaces for operators on complex Banach spaces to the context of operators on Hilbert space, and we gave easier…

Functional Analysis · Mathematics 2017-10-30 Il Bong Jung , Eungil Ko , Carl Pearcy

For truncated Toeplitz operators, which are compressions of multiplication operators to model subspaces of the Hardy space $H^2$, we obtain criteria for commutation relations. The results show an analogy to the case of Toeplitz matrices,…

Functional Analysis · Mathematics 2013-05-30 Isabelle Chalendar , Dan Timotin

Rearrangement-invariance in function spaces can be viewed as a kind of generalization of 1-symmetry for Schauder bases. We define subrearrangement-invariance in function spaces as an analogous generalization of 1-subsymmetry. It is then…

Functional Analysis · Mathematics 2021-01-06 Ben Wallis

Following Beurling's theorem and a study of the topology of invariant subspaces by R. Douglas and C. Pearcy description of path connected components of invariant subspace lattice for shift of multiplicity one has been given by R.Yang. This…

Functional Analysis · Mathematics 2011-01-18 Giorgi Shonia

It is known that invariant subspaces of classical Jordan blocks of the Hardy space over the open unit disc are described by factorizations of inner functions. In the polydisc setting, Jordan blocks are tensor products of one-variable Jordan…

Functional Analysis · Mathematics 2026-05-26 Sneha B , Jaydeb Sarkar , Michio Seto

This paper considers paired operators in the context of the Lebesgue Hilbert space $L^2$ on the unit circle and its subspace, the Hardy space $H^2$. The kernels of such operators, together with their analytic projections, which are…

Functional Analysis · Mathematics 2025-01-22 M. Cristina Câmara , Jonathan R. Partington

We develop the theory of variable exponent Hardy spaces. Analogous to the classical theory, we give equivalent definitions in terms of maximal operators. We also show that distributions in these spaces have an atomic decomposition including…

Classical Analysis and ODEs · Mathematics 2012-11-29 David Cruz-Uribe , SFO , Li-An Daniel Wang

If $T$ is a polynomially bounded operator, $\mathcal M$ is an invariant subspace of $T$, $T|_{\mathcal M}$ is a unilateral shift and $T^*|_{\mathcal M^\perp}$ is subnormal, then $T$ has a nontrivial hyperinvariant subspace. If an operator…

Functional Analysis · Mathematics 2025-09-09 Maria F. Gamal'

The Invariant Subspace Problem (ISP) for Hilbert spaces asks if every bounded linear operator has a non-trivial closed invariant subspace. Due to the existence of universal operators (in the sense of Rota) the ISP can be solved by proving…

Functional Analysis · Mathematics 2024-03-06 João Marcos R. do Carmo , Marcos S. Ferreira

Consider a Hilbert space obtained as the completion of the polynomials C[z} in m-variables for which the mnonomials are orthogonal. If the commuting weighted shifts defined by the coordinate functions are essentially normal, then the same…

Operator Algebras · Mathematics 2007-05-23 Ronald G. Douglas

Some special Hilbert spaces are introduced to present the class of infinitesimal operators with complete minimal non-basis family of eigenvectors. The discrete Hardy inequality plays an important role in the proposed approach. The…

Spectral Theory · Mathematics 2016-08-25 Grigory M. Sklyar , Vitalii Marchenko

This paper deals with representing in concrete fashion those Hilbert spaces that are vector subspaces of the Hardy spaces $H^p(\bb D^n) \ (1\le p\le \infty)$ that remain invariant under the action of coordinate wise multiplication by an…

Functional Analysis · Mathematics 2022-01-19 Sneh Lata , Sushant Pokhriyal , Dinesh Singh

This paper is concerned with paired operators in the context of the Lebesgue Hilbert space on the unit circle and its subspace, the Hardy space. By considering when such operators commute, generalizations of the Brown--Halmos results for…

Functional Analysis · Mathematics 2024-01-01 M. Cristina Câmara , André Guimarães , Jonathan R. Partington

The Grassmannian model represents harmonic maps from Riemann surfaces by families of shift-invariant subspaces of a Hilbert space. We impose a natural symmetry condition on the shift-invariant subspaces that corresponds to considering an…

Functional Analysis · Mathematics 2019-12-06 Alexandru Aleman , Rui Pacheco , John C. Wood

We generalise the result of Berger and Shaw the trace formula for Hardy Hilbert space to a larger class of rotation invariant Hilbert function spaces on the unit disk. We also demonstrate many meaningful examples of these Hilbert spaces by…

Functional Analysis · Mathematics 2025-08-06 Nathan Parker

In a wide class of weighted Bergman spaces, we construct invertible non-cyclic elements. These are then used to produce z-invariant subspaces of index higher than one. In addition, these elements generate nontrivial bilaterally invariant…

Functional Analysis · Mathematics 2007-05-23 Alexander Borichev , Hakan Hedenmalm , Alexander Volberg
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