Abstract
Numerical range has an important applications on spectrum distribution of operators. In this paper, we devoted to characterizing operators whose numerical range contains the origin. Some necessary and sufficient conditions are given by operator decomposition technique and constructive methods. Furthermore, the closeness of the numerical range of a given operator is also investigated.
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Acknowledgements
Thank to the referees for several remarks and carefully review of this paper, especially on Theorem 2.8.
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Supported by the NNSF of China (Grant Nos. 11761029, 11461049, 11371185, 11661034 and 11761055), the NSF of Inner Mongolia (Grant No. 2017MS0123), and the key Science and Technology Program of Colleges and Universities of Inner Mogolia (Grant No. NJZY17234)
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Wu, X.H., Huang, J.J. & Alatancang On the Origin and Numerical Range of Bounded Operators. Acta. Math. Sin.-English Ser. 35, 1715–1722 (2019). https://doi.org/10.1007/s10114-019-8478-2
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DOI: https://doi.org/10.1007/s10114-019-8478-2