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Holomorphic Idempotents and Retracts in the Unit Ball of a Commutative C*-Algebra with Identity

✍ Scribed by Jerry R. Muir Jr.


Publisher
Elsevier Science
Year
2000
Tongue
English
Weight
189 KB
Volume
247
Category
Article
ISSN
0022-247X

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✦ Synopsis


Let A be a commutative C U -algebra with identity and open unit ball B. We study holomorphic functions F: B ª B that are idempotent under composition and establish necessary and sufficient conditions for a set R : B to be the image Ž of B under such an idempotent function. In other words, R is a holomorphic . retract of B. In order to achieve this result, a representation for linear idempotents of the algebra must be attained. The linear part of a holomorphic idempotent taking 0 to 0 is idempotent itself, and thus the linear representation can be used to prove several identities relating the linear and holomorphic idempotents, giving the main result.