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The sequential stability index of a function space

Published online by Cambridge University Press:  26 February 2010

J. M. Anderson
Affiliation:
Department of Mathematics, University College London.
J. E. Jayne
Affiliation:
Department of Mathematics, University College London.
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Extract

One of the substantial differences between real and complex analysis is the behaviour of pointwise sequential limits of functions. It is well known that, if f(z) is a bounded analytic function in D = {zC: |z| < 1}, then there exists a sequence {pn(z): n = 1,2,…} of polynomials such that

(i) ‖Pn‖ ≤ ‖f‖ for all n = 1,2,3,…, and

(ii) for each zD, Pn(Z) → f(z) as n → ∞,

where we have used the notation

Type
Research Article
Copyright
Copyright © University College London 1973

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References

1. Jayne, J. E., “Descriptive set theory in compact spaces”, Amer. Math. Soc. Notices, 17 (1970), 268.Google Scholar
2. Kuratowski, K., “Sur une généralisation de la notion d'homéomorphie”, Fund. Math., 22 (1934), 206220.CrossRefGoogle Scholar
3. Kuratowski, K., Topology, Vol. 1 (Academic Press, New York, 1966).Google Scholar
4. Landau, E., Darstellung und Begründung einiger neuerer Ergebnisse der Funktionentheorie (Berlin, 1929).Google Scholar
5. Lebesgue, H., “Sur les fonctions représentables analytiquement”, Jour, de Math., 1 (1905), 139216.Google Scholar
6. Pelczήski, A. and Semadeni, Z., “Spaces of continuous functions III. (The space C(X) for X without perfect subsets.)”, Studia Math., 18 (1959), 211222.CrossRefGoogle Scholar
7. Saks, S. and Zygmund, A., Analytic functions (Warszawa-Wroclaw, 1952).Google Scholar
8. Sarason, D., “On the order of a simply connected domain”, Michigan Math. J., 15 (1968), 129133.CrossRefGoogle Scholar