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arXiv · 1705.08223

A note on Anderson's theorem in the infinite-dimensional setting

Riddhick Birbonshi·Ilya M. Spitkovsky·P. D. Srivastava
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Abstract

Anderson's theorem states that if the numerical range W(A) of an n-by-n matrix A is contained in the unit disk and intersects with the unit circle at more than n points, then it coincides with the (closed) unit dissk. An analogue of this result for compact A in an infinite dimensional setting was established by Gau and Wu. We consider here the case of A being the sum of a normal and compact operator.

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Riddhick Birbonshi, Ilya M. Spitkovsky, P. D. Srivastava. 2017-05-23. A note on Anderson's theorem in the infinite-dimensional setting. https://arxiv.org/abs/1705.08223

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