Weighted Shifts on Directed Trees

Weighted Shifts on Directed Trees PDF Author: Zenon Jan Jablónski
Publisher: American Mathematical Soc.
ISBN: 0821868683
Category : Linear operators
Languages : en
Pages : 122

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Book Description
A new class of (not necessarily bounded) operators related to (mainly infinite) directed trees is introduced and investigated. Operators in question are to be considered as a generalization of classical weighted shifts, on the one hand, and of weighted adjacency operators, on the other; they are called weighted shifts on directed trees. The basic properties of such operators, including closedness, adjoints, polar decomposition and moduli are studied. Circularity and the Fredholmness of weighted shifts on directed trees are discussed. The relationships between domains of a weighted shift on a directed tree and its adjoint are described. Hyponormality, cohyponormality, subnormality and complete hyperexpansivity of such operators are entirely characterized in terms of their weights. Related questions that arose during the study of the topic are solved as well.

Weighted Shifts on Directed Trees

Weighted Shifts on Directed Trees PDF Author: Zenon Jan Jablónski
Publisher: American Mathematical Soc.
ISBN: 0821868683
Category : Linear operators
Languages : en
Pages : 122

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Book Description
A new class of (not necessarily bounded) operators related to (mainly infinite) directed trees is introduced and investigated. Operators in question are to be considered as a generalization of classical weighted shifts, on the one hand, and of weighted adjacency operators, on the other; they are called weighted shifts on directed trees. The basic properties of such operators, including closedness, adjoints, polar decomposition and moduli are studied. Circularity and the Fredholmness of weighted shifts on directed trees are discussed. The relationships between domains of a weighted shift on a directed tree and its adjoint are described. Hyponormality, cohyponormality, subnormality and complete hyperexpansivity of such operators are entirely characterized in terms of their weights. Related questions that arose during the study of the topic are solved as well.

Weighted Shifts on Directed Trees

Weighted Shifts on Directed Trees PDF Author: Zenon Jan Jablónski
Publisher: American Mathematical Soc.
ISBN: 0821885286
Category : Mathematics
Languages : en
Pages : 122

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Book Description


Handbook of Analytic Operator Theory

Handbook of Analytic Operator Theory PDF Author: Kehe Zhu
Publisher: CRC Press
ISBN: 1351045539
Category : Mathematics
Languages : en
Pages : 228

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Book Description
This handbook concerns the subject of holomorphic function spaces and operators acting on them. Topics include Bergman spaces, Hardy spaces, Besov/Sobolev spaces, Fock spaces, and the space of Dirichlet series. Operators discussed in the book include Toeplitz operators, Hankel operators, composition operators, and Cowen-Douglas class operators

Unbounded Weighted Composition Operators in L2-Spaces

Unbounded Weighted Composition Operators in L2-Spaces PDF Author: Piotr Budzyński
Publisher: Springer
ISBN: 3319740393
Category : Mathematics
Languages : en
Pages : 182

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Book Description
This book establishes the foundations of the theory of bounded and unbounded weighted composition operators in L2-spaces. It develops the theory in full generality, meaning that the corresponding composition operators are not assumed to be well defined. A variety of seminormality properties of unbounded weighted composition operators are characterized. The first-ever criteria for subnormality of unbounded weighted composition operators are provided and the subtle interplay between the classical moment problem, graph theory and the injectivity problem for weighted composition operators is revealed. The relationships between weighted composition operators and the corresponding multiplication and composition operators are investigated. The optimality of the obtained results is illustrated by a variety of examples, including those of discrete and continuous types. The book is primarily aimed at researchers in single or multivariable operator theory.

Multivariable Operator Theory

Multivariable Operator Theory PDF Author: Ernst Albrecht
Publisher: Springer Nature
ISBN: 3031505352
Category : Mathematics
Languages : en
Pages : 893

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Book Description
Over the course of his distinguished career, Jörg Eschmeier made a number of fundamental contributions to the development of operator theory and related topics. The chapters in this volume, compiled in his memory, are written by distinguished mathematicians and pay tribute to his many significant and lasting achievements.

Issues in General and Specialized Mathematics Research: 2013 Edition

Issues in General and Specialized Mathematics Research: 2013 Edition PDF Author:
Publisher: ScholarlyEditions
ISBN: 1490112162
Category : Mathematics
Languages : en
Pages : 1919

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Book Description
Issues in General and Specialized Mathematics Research: 2013 Edition is a ScholarlyEditions™ book that delivers timely, authoritative, and comprehensive information about General Mathematics. The editors have built Issues in General and Specialized Mathematics Research: 2013 Edition on the vast information databases of ScholarlyNews.™ You can expect the information about General Mathematics in this book to be deeper than what you can access anywhere else, as well as consistently reliable, authoritative, informed, and relevant. The content of Issues in General and Specialized Mathematics Research: 2013 Edition has been produced by the world’s leading scientists, engineers, analysts, research institutions, and companies. All of the content is from peer-reviewed sources, and all of it is written, assembled, and edited by the editors at ScholarlyEditions™ and available exclusively from us. You now have a source you can cite with authority, confidence, and credibility. More information is available at http://www.ScholarlyEditions.com/.

Zeta Functions for Two-Dimensional Shifts of Finite Type

Zeta Functions for Two-Dimensional Shifts of Finite Type PDF Author: Jung-Chao Ban
Publisher: American Mathematical Soc.
ISBN: 0821872907
Category : Mathematics
Languages : en
Pages : 60

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Book Description
This work is concerned with zeta functions of two-dimensional shifts of finite type. A two-dimensional zeta function $\zeta^{0}(s)$, which generalizes the Artin-Mazur zeta function, was given by Lind for $\mathbb{Z}^{2}$-action $\phi$. In this paper, the $n$th-order zeta function $\zeta_{n}$ of $\phi$ on $\mathbb{Z}_{n\times \infty}$, $n\geq 1$, is studied first. The trace operator $\mathbf{T}_{n}$, which is the transition matrix for $x$-periodic patterns with period $n$ and height $2$, is rotationally symmetric. The rotational symmetry of $\mathbf{T}_{n}$ induces the reduced trace operator $\tau_{n}$ and $\zeta_{n}=\left(\det\left(I-s^{n}\tau_{n}\right)\right)^{-1}$. The zeta function $\zeta=\prod_{n=1}^{\infty} \left(\det\left(I-s^{n}\tau_{n}\right)\right)^{-1}$ in the $x$-direction is now a reciprocal of an infinite product of polynomials. The zeta function can be presented in the $y$-direction and in the coordinates of any unimodular transformation in $GL_{2}(\mathbb{Z})$. Therefore, there exists a family of zeta functions that are meromorphic extensions of the same analytic function $\zeta^{0}(s)$. The natural boundary of zeta functions is studied. The Taylor series for these zeta functions at the origin are equal with integer coefficients, yielding a family of identities, which are of interest in number theory. The method applies to thermodynamic zeta functions for the Ising model with finite range interactions.

Notes on the Brown-Douglas-Fillmore Theorem

Notes on the Brown-Douglas-Fillmore Theorem PDF Author: Sameer Chavan
Publisher: Cambridge University Press
ISBN: 1316519309
Category : Mathematics
Languages : en
Pages : 259

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Book Description
The book discusses the complete proof of the Brown-Douglas-Fillmore theorem along with a number of its applications.

The Reflective Lorentzian Lattices of Rank 3

The Reflective Lorentzian Lattices of Rank 3 PDF Author: Daniel Allcock
Publisher: American Mathematical Soc.
ISBN: 0821869116
Category : Mathematics
Languages : en
Pages : 108

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Book Description
"November 2012, volume 220, Number 1033 (first of 4 numbers)."

A Theory of Generalized Donaldson-Thomas Invariants

A Theory of Generalized Donaldson-Thomas Invariants PDF Author: Dominic D. Joyce
Publisher: American Mathematical Soc.
ISBN: 0821852795
Category : Calabi-Yau manifolds
Languages : en
Pages : 199

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Book Description
This book studies generalized Donaldson-Thomas invariants $\bar{DT}{}^\alpha(\tau)$. They are rational numbers which `count' both $\tau$-stable and $\tau$-semistable coherent sheaves with Chern character $\alpha$ on $X$; strictly $\tau$-semistable sheaves must be counted with complicated rational weights. The $\bar{DT}{}^\alpha(\tau)$ are defined for all classes $\alpha$, and are equal to $DT^\alpha(\tau)$ when it is defined. They are unchanged under deformations of $X$, and transform by a wall-crossing formula under change of stability condition $\tau$. To prove all this, the authors study the local structure of the moduli stack $\mathfrak M$ of coherent sheaves on $X$. They show that an atlas for $\mathfrak M$ may be written locally as $\mathrm{Crit}(f)$ for $f:U\to{\mathbb C}$ holomorphic and $U$ smooth, and use this to deduce identities on the Behrend function $\nu_\mathfrak M$. They compute the invariants $\bar{DT}{}^\alpha(\tau)$ in examples, and make a conjecture about their integrality properties. They also extend the theory to abelian categories $\mathrm{mod}$-$\mathbb{C}Q\backslash I$ of representations of a quiver $Q$ with relations $I$ coming from a superpotential $W$ on $Q$.