Essential spectra of weighted composition operators induced by elliptic automorphisms
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DOI: 10.1007/s00209-021-02880-x
Abstract: The spectrum of a weighted composition operator $C_{\psi, \varphi}$ who is induced by an automorphism has been investigated for over fifty years. However, many results are got only under the condition that the weight function… read more here.
Keywords: essential spectra; weighted composition; spectra weighted; composition operators ... See more keywords
Approximation of eigenvalues below the essential spectra of singular second-order symmetric linear difference equations
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DOI: 10.1007/s11425-016-0223-9
Abstract: This paper is concerned with approximation of eigenvalues below the essential spectra of singular second-order symmetric linear difference equations with at least one endpoint in the limit point case. A sufficient condition is firstly given… read more here.
Keywords: order symmetric; second order; singular second; eigenvalues essential ... See more keywords
Stability of some essential spectra of closed linear relations on Banach spaces
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DOI: 10.1007/s13370-018-0595-z
Abstract: This paper is devoted to the investigation of the stability of some essential spectra of a closed linear relation T on a Banach space X, subjected to additive perturbations K by imposing some conditions on… read more here.
Keywords: closed linear; essential spectra; spectra closed; stability essential ... See more keywords
Characterization of Essential Spectra Involving Weakly Demicompact Operators on Banach Spaces
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DOI: 10.1007/s41980-021-00598-4
Abstract: In this paper, we prove that a weakly demicompact linear operator with respect to an unbounded operator $$S_{0}$$ can be characterized by measures of weak noncompactness. Moreover, its relationship with semi-Fredholm operators as well as… read more here.
Keywords: involving weakly; spectra involving; essential spectra; characterization essential ... See more keywords