scholarly journals On local spectral properties of Hamilton operators

Filomat ◽  
2018 ◽  
Vol 32 (7) ◽  
pp. 2563-2566
Author(s):  
Wurichaihu Bai ◽  
Alatancang Chen
Keyword(s):  
Spectral Properties ◽  
Hyperinvariant Subspace ◽  
Weyl Type Theorems ◽  
Subspace Problem ◽  
Adjoint Operators

This paper deals with local spectral properties of Hamilton type operators. The strongly decomposability, Weyl type theorems and hyperinvariant subspace problem of them and the similar properties with their adjoint operators are studied. As corollaries, some local spectral properties of Hamilton operators are obtained.

scholarly journals Local Spectral Properties Under Conjugations

2021 ◽  
Vol 18 (3) ◽  
Author(s):  
Pietro Aiena ◽  
Fabio Burderi ◽  
Salvatore Triolo
Keyword(s):  
Hilbert Space ◽  
Spectral Properties ◽  
Operator Matrices ◽  
Weyl Type Theorems ◽  
Triangular Operator ◽  
Analytic Core ◽  
Complex Symmetric ◽  
Symmetric Operators ◽  
The Relationship

AbstractIn this paper, we study some local spectral properties of operators having form JTJ, where J is a conjugation on a Hilbert space H and $$T\in L(H)$$ T ∈ L ( H ) . We also study the relationship between the quasi-nilpotent part of the adjoint $$T^*$$ T ∗ and the analytic core K(T) in the case of decomposable complex symmetric operators. In the last part we consider Weyl type theorems for triangular operator matrices for which one of the entries has form JTJ, or has form $$JT^*J$$ J T ∗ J . The theory is exemplified in some concrete cases.

Quasidiagonality and the hyperinvariant subspace problem

2008 ◽  
Vol 166 (1) ◽  
pp. 285-296
Author(s):  
Sami M. Hamid ◽  
Constantin Onica ◽  
Carl Pearcy
Keyword(s):  
Hyperinvariant Subspace ◽  
Subspace Problem

scholarly journals INTEGER OPERATORS IN FINITE VON NEUMANN ALGEBRAS

2011 ◽  
Vol 03 (04) ◽  
pp. 433-450
Author(s):  
ANDREAS THOM
Keyword(s):  
Potential Theory ◽  
Spectral Properties ◽  
Von Neumann Algebras ◽  
Logarithmic Capacity ◽  
Integral Group ◽  
Von Neumann ◽  
Classical Potential ◽  
Classical Potential Theory ◽  
Adjoint Operators ◽  
Finite Von Neumann Algebras

Motivated by the study of spectral properties of self-adjoint operators in the integral group ring of a sofic group, we define and study integer operators. We establish a relation with classical potential theory and in particular the circle of results obtained by Fekete and Szegö, see [3, 4, 13]. More concretely, we use results by Rumely, see [12], on equidistribution of algebraic integers to obtain a description of those integer operator which have spectrum of logarithmic capacity less than or equal to one. Finally, we relate the study of integer operators to a recent construction by Petracovici and Zaharescu, see [10].

scholarly journals On spectra and Brown's spectral measures of elements in free products of matrix algebras

2008 ◽  
Vol 103 (1) ◽  
pp. 77
Author(s):  
Junsheng Fang ◽  
Don Hadwin ◽  
Xiujuan Ma
Keyword(s):  
Free Product ◽  
Von Neumann Algebra ◽  
Single Point ◽  
Diagonal Operator ◽  
Spectral Measures ◽  
Free Products ◽  
Hyperinvariant Subspace ◽  
Von Neumann ◽  
Matrix Algebras ◽  
Adjoint Operators

We compute spectra and Brown measures of some non self-adjoint operators in $(M_2(\mathsf {C}), \frac{1}{2}\mathrm{Tr})*(M_2(\mathsf{C}), \frac{1}{2}\mathrm{Tr})$, the reduced free product von Neumann algebra of $M_2(\mathsf {C})$ with $M_2(\mathsf {C})$. Examples include $AB$ and $A+B$, where $A$ and $B$ are matrices in $(M_2(\mathsf {C}), \frac{1}{2}\mathrm{Tr})*1$ and $1*(M_2(\mathsf {C}), \frac{1}{2}\mathrm{Tr})$, respectively. We prove that $AB$ is an R-diagonal operator (in the sense of Nica and Speicher [12]) if and only if $\mathrm{Tr}(A)=\mathrm{Tr}(B)=0$. We show that if $X=AB$ or $X=A+B$ and $A,B$ are not scalar matrices, then the Brown measure of $X$ is not concentrated on a single point. By a theorem of Haagerup and Schultz [9], we obtain that if $X=AB$ or $X=A+B$ and $X\neq \lambda 1$, then $X$ has a nontrivial hyperinvariant subspace affiliated with $(M_2(\mathsf{C}), \frac{1}{2}\mathrm{Tr})*(M_2(\mathsf{C}), \frac{1}{2}\mathrm{Tr})$.

On the Hyperinvariant Subspace Problem. IV

2008 ◽  
Vol 60 (4) ◽  
pp. 758-789 ◽  
Author(s):  
H. Bercovici ◽  
C. Foias ◽  
C. Pearcy
Keyword(s):  
Hilbert Space ◽  
Compact Operator ◽  
Essential Spectrum ◽  
Complete Lattice ◽  
Unit Disc ◽  
Diagonal Operator ◽  
Hyperinvariant Subspace ◽  
Infinite Dimensional ◽  
Infinite Dimensional Hilbert Space ◽  
Subspace Problem

AbstractThis paper is a continuation of three recent articles concerning the structure of hyperinvariant subspace lattices of operators on a (separable, infinite dimensional) Hilbert space . We show herein, in particular, that there exists a “universal” fixed block-diagonal operator B on such that if ε > 0 is given and T is an arbitrary nonalgebraic operator on , then there exists a compact operator K of norm less than ε such that (i) Hlat(T) is isomorphic as a complete lattice to Hlat(B + K) and (ii) B + K is a quasidiagonal, C00, (BCP)-operator with spectrum and left essential spectrum the unit disc. In the last four sections of the paper, we investigate the possible structures of the hyperlattice of an arbitrary algebraic operator. Contrary to existing conjectures, Hlat(T) need not be generated by the ranges and kernels of the powers of T in the nilpotent case. In fact, this lattice can be infinite.

scholarly journals Spectral Enclosures and Complex Resonances for General Self-Adjoint Operators

1998 ◽  
Vol 1 ◽  
pp. 42-74 ◽  
Author(s):  
E.B. Davies
Keyword(s):  
Spectral Properties ◽  
Linear Subspace ◽  
Adjoint Operator ◽  
Dimensional Linear Subspace ◽  
Finite Dimensional ◽  
Adjoint Operators ◽  
Computation Of Eigenvalues

AbstractThis paper considers a number of related problems concerning the computation of eigenvalues and complex resonances of a general self-adjoint operator H. The feature which ties the different sections together is that one restricts oneself to spectral properties of H which can be proved by using only vectors from a pre-assigned (possibly finite-dimensional) linear subspace L.

scholarly journals On the hyperinvariant subspace problem

2005 ◽  
Vol 219 (1) ◽  
pp. 134-142 ◽  
Author(s):  
Ciprian Foias ◽  
Carl Pearcy
Keyword(s):  
Hyperinvariant Subspace ◽  
Subspace Problem
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