Bulletin of the Korean Mathematical Society (대한수학회보)
- Volume 33 Issue 3
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- Pages.427-434
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- 1996
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- 1015-8634(pISSN)
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- 2234-3016(eISSN)
Spectra and numberical ranges
Abstract
The theory of numerical ranges in unital normed algebras has extensively studied by many authors, for examples, see [1], [2] for details.