We prove new spectral enclosures for the non-real spectrum of a class of 2×2 block operator matrices with self-adjoint operators A and D on the diagonal and operators B and -B* as off-diagonal entries. One of our main results resembles Gershgorin's circle theorem. The enclosures are applied to J-frame operators
Abstract. In this note we study spectral properties of a block operator matrix eA (see (1.1) below),...
In the first part of this manuscript a relationship between the spectrum of self-adjoint operator ma...
The numerical range and the quadratic numerical range is used to study the spectrum of a class of bl...
We prove new spectral enclosures for the non-real spectrum of a class of 2x2 block operator matrices...
We prove new spectral enclosures for the non-real spectrum of a class of 2x2 block operator matrices...
We prove new spectral enclosures for the non-real spectrum of a class of 2x2 block operator matrices...
We prove new spectral enclosures for the non-real spectrum of a class of 2x2 block operator matrices...
We prove new spectral enclosures for the non-real spectrum of a class of 2 × 2 block operator matric...
We study the spectrum of unbounded J-self-adjoint block operator matrices. In particular, we prove e...
We study the spectrum of unbounded J-self-adjoint block operator matrices. In particular, we prove e...
We study the spectrum of unbounded J-self-adjoint block operator matrices. In particular, we prove e...
AbstractIn this paper we establish a new analytic enclosure for the spectrum of unbounded linear ope...
We study the spectrum of unbounded JJ -self-adjoint block operator matrices. In particular, we prove...
In this paper, we establish an analytic enclosure for the spectrum of unbounded linear operators ~A ...
In this paper, we establish an analytic enclosure for the spectrum of unbounded linear operators ~A ...
Abstract. In this note we study spectral properties of a block operator matrix eA (see (1.1) below),...
In the first part of this manuscript a relationship between the spectrum of self-adjoint operator ma...
The numerical range and the quadratic numerical range is used to study the spectrum of a class of bl...
We prove new spectral enclosures for the non-real spectrum of a class of 2x2 block operator matrices...
We prove new spectral enclosures for the non-real spectrum of a class of 2x2 block operator matrices...
We prove new spectral enclosures for the non-real spectrum of a class of 2x2 block operator matrices...
We prove new spectral enclosures for the non-real spectrum of a class of 2x2 block operator matrices...
We prove new spectral enclosures for the non-real spectrum of a class of 2 × 2 block operator matric...
We study the spectrum of unbounded J-self-adjoint block operator matrices. In particular, we prove e...
We study the spectrum of unbounded J-self-adjoint block operator matrices. In particular, we prove e...
We study the spectrum of unbounded J-self-adjoint block operator matrices. In particular, we prove e...
AbstractIn this paper we establish a new analytic enclosure for the spectrum of unbounded linear ope...
We study the spectrum of unbounded JJ -self-adjoint block operator matrices. In particular, we prove...
In this paper, we establish an analytic enclosure for the spectrum of unbounded linear operators ~A ...
In this paper, we establish an analytic enclosure for the spectrum of unbounded linear operators ~A ...
Abstract. In this note we study spectral properties of a block operator matrix eA (see (1.1) below),...
In the first part of this manuscript a relationship between the spectrum of self-adjoint operator ma...
The numerical range and the quadratic numerical range is used to study the spectrum of a class of bl...
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