Hostname: page-component-76fb5796d-r6qrq Total loading time: 0 Render date: 2024-04-27T04:03:24.076Z Has data issue: false hasContentIssue false

Borel selectors for upper semi-continuous multi-valued functions

Published online by Cambridge University Press:  26 February 2010

J. E. Jayne
Affiliation:
Department of Mathematics, University College London, London, WC1E 6BT
C. A. Rogers
Affiliation:
Department of Mathematics, University College London, Gower Street, London, WC1E 6BT
Get access

Extract

In our paper [12[ we made extensive use of the details of the proofs given in our earlier paper [11], and, in particular, we claimed that Lemma 3 of [11] holds, not just when Y is a metric space, but also when Y is a Hausdorff space, provided X × Y is a Fréchet space. In a corrigendum to [11], we give a corrected version of this Lemma 3, but it seems to depend, in an essential way, on the assumption that Y is a metric space, or at least a perfectly normal space. In this note we show that a modified version of this Lemma 3 enables us to justify all the theorems in [12] by use of a modified method of selection.

Type
Research Article
Copyright
Copyright © University College London 1985

Access options

Get access to the full version of this content by using one of the access options below. (Log in options will check for institutional or personal access. Content may require purchase if you do not have access.)

References

1.Bessaga, C. and Pelczynski, A.. Selected Topics in Infinite-Dimensional Topology (PWN, Warsaw, 1975).Google Scholar
2.Borsuk, K.. Theory of Retracts, Mono. Mat. (PWN, Warsaw, 1967).Google Scholar
3.Borsuk, K.. Theory of Shape, Mono. Mat. (PWN, Warsaw, 1975).Google Scholar
4.Borsuk, K.. Uber Isomorphie der Funktional Raume. Bull Acad. Polon. Set., Ser. A, (1933), 110.Google Scholar
5.Dugundji, J.. An extension of Tietze's theorem. Pacific J. Math., 1 (1951), 353367.Google Scholar
6.Edgar, G. A.. Measurability in a Banach space. Indiana Univ. Math. J., 26 (1977), 663677.CrossRefGoogle Scholar
7.Hansell, R. W.. Borel measurable mappings for nonseparable metric spaces. Trans. Amer. Math. Soc, 161 (1971), 145169.CrossRefGoogle Scholar
8.Hansell, R. W.. On Borel mappings and Baire functions. Trans. Amer. Math. Soc, 194 (1974), 195211.Google Scholar
9.Hansell, R. W., Jayne, J. E., Labuda, I. and Rogers, C. A.. Boundaries of and selectors for upper semi-continuous set-valued functions. Math. Zeit., 189 (1985), 297318.CrossRefGoogle Scholar
10.Hu, S. T.. Theory of Retracts (Detroit, 1965).Google Scholar
11.Jayne, J. E. and Rogers, C. A.. Upper semi-continuous set-valued functions. Acta Math., 149 (1982), 87125, and a Corrigendum Acta Math. 155 (1985), 149–152.CrossRefGoogle Scholar
12.Jayne, J. E. and Rogers, C. A.. Borel selectors for upper semi-continuous multi-valued functions. J. Funct. Anal, 56 (1984), 279299.CrossRefGoogle Scholar