Abstract
It is well known that the identity is an operator with the following property: if the operator, initially defined on an -dimensional Banach space , can be extended to any Banach space with norm , then is isometric to . We show that the set of all such operators consists precisely of those with spectrum lying in the unit circle. This result answers a question raised in [5] for complex spaces.
Citation
B. L. Chalmers. B. Shekhtman. "Spectral properties of operators that characterize $\ell^{(n)}_\infty$." Abstr. Appl. Anal. 3 (3-4) 237 - 246, 1998. https://doi.org/10.1155/S1085337598000542
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