A REMARK ON BOUNDEDNESS OF THE NUMERICAL RANGE

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Published: Sep 1, 1991
DOI: https://doi.org/10.5556/j.tkjm.22.1991.4611
Keywords:
boundedness of the numerical range Hermitian matrix minimum (maximum) eigenvalue counter-example complex matrices

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CHI FAI CHAN
Department of Mathematics, University of Hong Kong, Hong Kong.

Abstract




It is shown that Chien's result on the smallest rectangle wjth sjdes parallel to the axes containing the nwnerical range of a real matrix follows from a simple observation on complex matrices. A counter-example to Chien's conjecture is also given.




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How to Cite
CHAN, C. F. (1991). A REMARK ON BOUNDEDNESS OF THE NUMERICAL RANGE. Tamkang Journal of Mathematics, 22(3), 271–273. https://doi.org/10.5556/j.tkjm.22.1991.4611
Issue
Vol. 22 No. 3 (1991)
Section
Papers
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References

M. T. Chien, "Boundedness of the numerical range", Linear Algebra Appl.·134, 25-30, 1990.

F. R. Gantmacher, The. Theory of Matrices, Vol. I, Chelsea Publishing Company, New York, 1959.