Operator Theory and the Corona Problem on the Bidisk

2004 ◽  
pp. 553-568
Author(s):  
Tavan T. Trent
Keyword(s):  
Operator Theory ◽  
Corona Problem

ON AN OPERATOR THEORY APPROACH TO THE CORONA PROBLEM

2002 ◽  
Vol 34 (3) ◽  
pp. 369-373
Author(s):  
E. AMAR ◽  
C. MENINI
Keyword(s):  
Operator Theory ◽  
Negative Answer ◽  
The Other ◽  
Theory Approach ◽  
Corona Problem ◽  
Natural Approach ◽  
Counter Example ◽  
Other Hand ◽  
Commutant Lifting

This paper deals with an operator theory approach to the corona conjecture for H∞([ ]n). Treil gave a counter-example to this conjecture in the case where n = 1 for operator-valued functions; thus one might hope to use this to disprove the corona conjecture for H∞([ ]n) (for n [ges ] 2). This paper shows that this natural approach towards a negative answer fails. On the other hand, the second result here shows that ‘commutant lifting’ cannot be true for more than two contractions for any constant. This obstructs a natural attempted proof of the corona conjecture for H∞([ ]n) (for n [ges ] 2) by our previous result.

Cline’s formula for g-Drazin inverses in a ring

Filomat ◽  
2019 ◽  
Vol 33 (8) ◽  
pp. 2249-2255
Author(s):  
Huanyin Chen ◽  
Marjan Abdolyousefi
Keyword(s):  
Operator Theory ◽  
Spectral Properties ◽  
Associative Ring ◽  
Linear Operators ◽  
Drazin Inverse ◽  
Bounded Linear Operators ◽  
Bounded Linear ◽  
Cline’S Formula

It is well known that for an associative ring R, if ab has g-Drazin inverse then ba has g-Drazin inverse. In this case, (ba)d = b((ab)d)2a. This formula is so-called Cline?s formula for g-Drazin inverse, which plays an elementary role in matrix and operator theory. In this paper, we generalize Cline?s formula to the wider case. In particular, as applications, we obtain new common spectral properties of bounded linear operators.

Quantum Resonances: Line Profiles and Dynamics

2003 ◽  
Vol 68 (3) ◽  
pp. 529-553 ◽  
Author(s):  
Ivana Paidarová ◽  
Philippe Durand
Keyword(s):  
Hydrogen Atom ◽  
Operator Theory ◽  
Quantum Dynamics ◽  
Line Profiles ◽  
Static Electric Field ◽  
Reversal Effect ◽  
Quantum Resonances ◽  
Energy Dependent ◽  
Effective Hamiltonians

The wave operator theory of quantum dynamics is reviewed and applied to the study of line profiles and to the determination of the dynamics of interacting resonances. Energy-dependent and energy-independent effective Hamiltonians are investigated. The q-reversal effect in spectroscopy is interpreted in terms of interfering Fano profiles. The dynamics of an hydrogen atom subjected to a strong static electric field is revisited.

scholarly journals Operator theory on quaternionic Hilbert spaces

1972 ◽  
Vol 7 (2) ◽  
pp. 297-299
Author(s):  
Neil Charles Powers
Keyword(s):  
Hilbert Spaces ◽  
Operator Theory

scholarly journals Regular approximation of singular Sturm–Liouville problems with eigenparameter dependent boundary conditions

2020 ◽  
Vol 2020 (1) ◽  
Author(s):  
Maozhu Zhang ◽  
Kun Li ◽  
Hongxiang Song
Keyword(s):  
Boundary Conditions ◽  
Operator Theory ◽  
Resolvent Convergence ◽  
Spectral Inclusion ◽  
Regular Approximation ◽  
Special Cases ◽  
Abstract Operator ◽  
Norm Resolvent Convergence ◽  
Sturm Liouville ◽  
Spectral Exactness

AbstractIn this paper we consider singular Sturm–Liouville problems with eigenparameter dependent boundary conditions and two singular endpoints. The spectrum of such problems can be approximated by those of the inherited restriction operators constructed. Via the abstract operator theory, the strongly resolvent convergence and norm resolvent convergence of a sequence of operators are obtained and it follows that the spectral inclusion of spectrum holds. Moreover, spectral exactness of spectrum holds for two special cases.

Analyzing Effectiveness of Gang Interventions using Koopman Operator Theory

2020 ◽  
Author(s):  
Sian Wen ◽  
Andy Chen ◽  
Tanishq Bhatia ◽  
Nicholas Liskij ◽  
David Hyde ◽  
...  
Keyword(s):  
Operator Theory ◽  
Koopman Operator ◽  
Gang Interventions
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