Unitary Invariants in Multivariable Operator Theory

Unitary Invariants in Multivariable Operator Theory PDF Author: Gelu Popescu
Publisher: American Mathematical Soc.
ISBN: 0821843966
Category : Mathematics
Languages : en
Pages : 105

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Book Description
This paper concerns unitary invariants for $n$-tuples $T:=(T_1,\ldots, T_n)$ of (not necessarily commuting) bounded linear operators on Hilbert spaces. The author introduces a notion of joint numerical radius and works out its basic properties. Multivariable versions of Berger's dilation theorem, Berger-Kato-Stampfli mapping theorem, and Schwarz's lemma from complex analysis are obtained. The author studies the joint (spatial) numerical range of $T$ in connection with several unitary invariants for $n$-tuples of operators such as: right joint spectrum, joint numerical radius, euclidean operator radius, and joint spectral radius. He also proves an analogue of Toeplitz-Hausdorff theorem on the convexity of the spatial numerical range of an operator on a Hilbert space, for the joint numerical range of operators in the noncommutative analytic Toeplitz algebra $F_n^\infty$.

Unitary Invariants in Multivariable Operator Theory

Unitary Invariants in Multivariable Operator Theory PDF Author: Gelu Popescu
Publisher: American Mathematical Soc.
ISBN: 0821843966
Category : Mathematics
Languages : en
Pages : 105

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Book Description
This paper concerns unitary invariants for $n$-tuples $T:=(T_1,\ldots, T_n)$ of (not necessarily commuting) bounded linear operators on Hilbert spaces. The author introduces a notion of joint numerical radius and works out its basic properties. Multivariable versions of Berger's dilation theorem, Berger-Kato-Stampfli mapping theorem, and Schwarz's lemma from complex analysis are obtained. The author studies the joint (spatial) numerical range of $T$ in connection with several unitary invariants for $n$-tuples of operators such as: right joint spectrum, joint numerical radius, euclidean operator radius, and joint spectral radius. He also proves an analogue of Toeplitz-Hausdorff theorem on the convexity of the spatial numerical range of an operator on a Hilbert space, for the joint numerical range of operators in the noncommutative analytic Toeplitz algebra $F_n^\infty$.

Multivariable Operator Theory

Multivariable Operator Theory PDF Author: Raúl E. Curto
Publisher: American Mathematical Soc.
ISBN: 0821802984
Category : Mathematics
Languages : en
Pages : 380

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Book Description
This volume contains a collection of papers presented at the Summer Research Conference on Multivariable Operator Theory, held in July 1993 at the University of Washington in Seattle. The articles contain contributions to a variety of areas and topics which may be viewed as forming an emerging new subject. This subject involves the study of geometric rather than topological invariants associated with the general theme of operator theory in several variables. Developments have occurred in several different directions, with the aid of a variety of techniques, and many advances have been made through cross-pollination among different areas of mathematics. The goal of the conference, and of this volume, is to spur discussion of the connections among the various approaches and new directions for research.

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.

Operator Theory on Noncommutative Domains

Operator Theory on Noncommutative Domains PDF Author: Gelu Popescu
Publisher: American Mathematical Soc.
ISBN: 0821847104
Category : Dilation theory (Operator theory).
Languages : en
Pages : 137

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Book Description
"Volume 205, number 964 (third of 5 numbers)."

Operator Algebras for Multivariable Dynamics

Operator Algebras for Multivariable Dynamics PDF Author: Kenneth R. Davidson
Publisher: American Mathematical Soc.
ISBN: 0821853023
Category : Mathematics
Languages : en
Pages : 53

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Book Description
Let $X$ be a locally compact Hausdorff space with $n$ proper continuous self maps $\sigma_i:X \to X$ for $1 \le i \le n$. To this the authors associate two conjugacy operator algebras which emerge as the natural candidates for the universal algebra of the system, the tensor algebra $\mathcal{A}(X,\tau)$ and the semicrossed product $\mathrm{C}_0(X)\times_\tau\mathbb{F}_n^+$. They develop the necessary dilation theory for both models. In particular, they exhibit an explicit family of boundary representations which determine the C*-envelope of the tensor algebra.|Let $X$ be a locally compact Hausdorff space with $n$ proper continuous self maps $\sigma_i:X \to X$ for $1 \le i \le n$. To this the authors associate two conjugacy operator algebras which emerge as the natural candidates for the universal algebra of the system, the tensor algebra $\mathcal{A}(X,\tau)$ and the semicrossed product $\mathrm{C}_0(X)\times_\tau\mathbb{F}_n^+$. They develop the necessary dilation theory for both models. In particular, they exhibit an explicit family of boundary representations which determine the C*-envelope of the tensor algebra.

Lyapunov Exponents and Invariant Manifolds for Random Dynamical Systems in a Banach Space

Lyapunov Exponents and Invariant Manifolds for Random Dynamical Systems in a Banach Space PDF Author: Zeng Lian
Publisher: American Mathematical Soc.
ISBN: 0821846566
Category : Banach spaces
Languages : en
Pages : 119

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Book Description
The authors study the Lyapunov exponents and their associated invariant subspaces for infinite dimensional random dynamical systems in a Banach space, which are generated by, for example, stochastic or random partial differential equations. The authors prove a multiplicative ergodic theorem and then use this theorem to establish the stable and unstable manifold theorem for nonuniformly hyperbolic random invariant sets.

Mixed-Norm Inequalities and Operator Space $L_p$ Embedding Theory

Mixed-Norm Inequalities and Operator Space $L_p$ Embedding Theory PDF Author: Marius Junge
Publisher: American Mathematical Soc.
ISBN: 0821846558
Category : Banach spaces
Languages : en
Pages : 168

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Book Description
Contains the proof of a noncommutative analogue of the inequality for sums of free random variables over a given von Neumann subalgebra.

Cohomological Invariants: Exceptional Groups and Spin Groups

Cohomological Invariants: Exceptional Groups and Spin Groups PDF Author: Skip Garibaldi
Publisher: American Mathematical Soc.
ISBN: 0821844040
Category : Mathematics
Languages : en
Pages : 102

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Book Description
This volume concerns invariants of $G$-torsors with values in mod $p$ Galois cohomology--in the sense of Serre's lectures in the book Cohomological invariants in Galois cohomology--for various simple algebraic groups $G$ and primes $p$. The author determines the invariants for the exceptional groups $F_4$ mod 3, simply connected $E_6$ mod 3, $E_7$ mod 3, and $E_8$ mod 5. He also determines the invariants of $\mathrm{Spin}_n$ mod 2 for $n \leq 12$ and constructs some invariants of $\mathrm{Spin}_{14}$. Along the way, the author proves that certain maps in nonabelian cohomology are surjective. These surjectivities give as corollaries Pfister's results on 10- and 12-dimensional quadratic forms and Rost's theorem on 14-dimensional quadratic forms. This material on quadratic forms and invariants of $\mathrm{Spin}_n$ is based on unpublished work of Markus Rost. An appendix by Detlev Hoffmann proves a generalization of the Common Slot Theorem for 2-Pfister quadratic forms.

Invariant Representations of $\mathrm {GSp}(2)$ under Tensor Product with a Quadratic Character

Invariant Representations of $\mathrm {GSp}(2)$ under Tensor Product with a Quadratic Character PDF Author: Ping-Shun Chan
Publisher: American Mathematical Soc.
ISBN: 0821848224
Category : Automorphisms
Languages : en
Pages : 185

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Book Description
"Volume 204, number 957 (first of 5 numbers)."

Harmonic Analysis of Operators on Hilbert Space

Harmonic Analysis of Operators on Hilbert Space PDF Author: Béla Sz Nagy
Publisher: Springer Science & Business Media
ISBN: 1441960937
Category : Mathematics
Languages : en
Pages : 481

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Book Description
The existence of unitary dilations makes it possible to study arbitrary contractions on a Hilbert space using the tools of harmonic analysis. The first edition of this book was an account of the progress done in this direction in 1950-70. Since then, this work has influenced many other areas of mathematics, most notably interpolation theory and control theory. This second edition, in addition to revising and amending the original text, focuses on further developments of the theory, including the study of two operator classes: operators whose powers do not converge strongly to zero, and operators whose functional calculus (as introduced in Chapter III) is not injective. For both of these classes, a wealth of material on structure, classification and invariant subspaces is included in Chapters IX and X. Several chapters conclude with a sketch of other developments related with (and developing) the material of the first edition.