Complex Extremal Structure in Spaces of Continuous Functions
✍ Scribed by A Jiménez-Vargas; J.F Mena-Jurado; J.C Navarro-Pascual
- Publisher
- Elsevier Science
- Year
- 1997
- Tongue
- English
- Weight
- 213 KB
- Volume
- 211
- Category
- Article
- ISSN
- 0022-247X
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✦ Synopsis
This paper considers the space Y s C T, X of all continuous and bounded functions from a topological space T to a complex normed space X with the sup Ž . norm. The extremal structure of the closed unit ball B Y in Y has been intensively studied when X is strictly convex, that is, in terms of its unitary Ž . functions mappings from T into the unit sphere of X . We prove that if T is Ž . completely regular and X has finite dimension, then every function in B Y is expressible as a convex combination of three unitary functions if and only if the
and X denotes X considered as a real normed space . If X is infinite-dimen-ޒ sional the above decomposition is always possible without restrictions about T. These results are interesting when X is complex strictly convex. As a consequence we state a surprising fact: The identity function on the unit ball of an infinite-
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