scholarly journals Decomposability of Krein space operators

Filomat ◽  
2020 ◽  
Vol 34 (9) ◽  
pp. 3119-3129
Author(s):  
Il An ◽  
Jaeseong Heo
Keyword(s):  
Spectral Theory ◽  
Selfadjoint Operator ◽  
Krein Space ◽  
Selfadjoint Operators ◽  
Kreĭn Space ◽  
Decomposable Operators ◽  
Spectral Subspaces ◽  
Local Spectral Theory

In this paper, we review some properties in the local spectral theory and various subclasses of decomposable operators. We prove that every Krein space selfadjoint operator having property (?) is decomposable, and clarify the relation between decomposability and property (?) for J-selfadjoint operators. We prove the equivalence of these properties for J-selfadjoint operators T and T* by using their local spectra and local spectral subspaces.

Some remarks on a paper by W. N. Everitt

1977 ◽  
Vol 78 (1-2) ◽  
pp. 71-79 ◽  
Author(s):  
K. Daho ◽  
H. Langer
Keyword(s):  
Hilbert Space ◽  
Weight Function ◽  
Selfadjoint Operator ◽  
Krein Space ◽  
Indefinite Weight ◽  
Indefinite Weight Function ◽  
Kreĭn Space ◽  
Pontrjagin Space

Everitt has shown [1[, that for α ∊ [0, π/2] the undernoted problem (1.1–2) with an indefinite weight function r can be represented by a selfadjoint operator in a suitable Hilbert space. This result is extended to arbitrary α ∊ [0, π), replacing the Hilbert space in some cases by a Pontrjagin space with index one. The problem is also treated in the Krein space generated by the weight function r.

scholarly journals Weyl type theorems for selfadjoint operators on Krein spaces

Filomat ◽  
2018 ◽  
Vol 32 (17) ◽  
pp. 6001-6016
Author(s):  
Il An ◽  
Jaeseong Heo
Keyword(s):  
Hilbert Space ◽  
Linear Operator ◽  
Krein Space ◽  
Linear Operators ◽  
Fredholm Theory ◽  
Bounded Linear ◽  
Selfadjoint Operators ◽  
Krein Spaces ◽  
Weyl Type Theorems ◽  
Kreĭn Space

In this paper, we introduce a notion of the J-kernel of a bounded linear operator on a Krein space and study the J-Fredholm theory for Krein space operators. Using J-Fredholm theory, we discuss when (a-)J-Weyl?s theorem or (a-)J-Browder?s theorem holds for bounded linear operators on a Krein space instead of a Hilbert space.

scholarly journals Existence theorems for Segal quantization via spectral theory in Krein space

1983 ◽  
Vol 24 (4) ◽  
pp. 439-460 ◽  
Author(s):  
P. Broadbridge
Keyword(s):  
Spectral Theory ◽  
Polar Decomposition ◽  
Existence Theorems ◽  
Krein Space ◽  
Complex Structure ◽  
Adjoint Operator ◽  
Classical Solutions ◽  
Indefinite Metric ◽  
Orthogonal Component ◽  
Kreĭn Space

AbstractSegal's unitarizing complex structure J is shown, in the Fermi-Dirac case, to be the orthogonal component in the polar decomposition of the real skew adjoint generator of classical dynamics. It is proven that in the Bose-Einstein case, the classical symplectic dynamics cannot be unitarized unless the generator is similar to a real skew adjoint operator.With the classical Hamiltonian strictly positive, J is the pseudo-orthogonal component in the polar decomposition of the generator, using spectral theory in Krein space with indefinite metric. Thus, J can be expressed simply in terms of the projection E(0) onto the subspace of classical solutions with negative frequency. This complements the physicists' experience that conceptual difficulties arise when dynamically invariant separation of positive and negative frequency solutions is impossible.

Krein Space-based Hθ Fault Estimation for Linear Discrete Time-varying Systems

2009 ◽  
Vol 34 (12) ◽  
pp. 1529-1533 ◽  
Author(s):  
Mai-Ying ZHONG ◽  
Shuai LIU ◽  
Hui-Hong ZHAO
Keyword(s):  
Discrete Time ◽  
Krein Space ◽  
Fault Estimation ◽  
Time Varying ◽  
Time Varying Systems ◽  
Kreĭn Space
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