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Proceedings of the American Mathematical Society
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Noncoherence of some rings of functions

Author(s): Amol Sasane
Journal: Proc. Amer. Math. Soc. 135 (2007), 2107-2111.
MSC (2000): Primary 46J15, 30A98; Secondary 93C05, 13E15
Posted: February 6, 2007
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Abstract: Let $ \mathbb{D}$, $ \mathbb{T}$ denote the unit disc and unit circle, respectively, in $ \mathbb{C}$, with center 0. If $ S\subset \mathbb{T}$, then let $ A_{S}$ denote the set of complex-valued functions defined on $ \mathbb{D}\cup S$ that are analytic in $ \mathbb{D}$, and continuous and bounded on $ \mathbb{D}\cup S$. Then $ A_{S}$ is a ring with pointwise addition and multiplication. We prove that if the intersection of $ S$ with the set of limit points of $ S$ is not empty, then the ring $ A_{S}$ is not coherent.


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Additional Information:

Amol Sasane
Affiliation: Department of Mathematics, London School of Economics, Houghton Street, London WC2A 2AE, United Kingdom
Email: A.J.Sasane@lse.ac.uk

DOI: 10.1090/S0002-9939-07-08704-7
PII: S 0002-9939(07)08704-7
Keywords: Banach algebras of analytic functions, coherent rings
Received by editor(s): September 20, 2005
Received by editor(s) in revised form: March 10, 2006
Posted: February 6, 2007
Communicated by: Joseph A. Ball
Copyright of article: Copyright 2007, American Mathematical Society
The copyright for this article reverts to public domain after 28 years from publication.


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