ArticleOriginal scientific text
Title
When are Borel functions Baire functions?
Authors 1
Affiliations
- Cowiconsult, Consulting Engineers and Planners AS, 15, Parallelvej, Dk-2800 Lyngby, Denmark
Abstract
The following two theorems give the flavour of what will be proved. Theorem. Let Y be a complete metric space. Then the families of first Baire class functions and of first Borel class functions from [0,1] to Y coincide if and only if Y is connected and locally connected.} Theorem. Let Y be a separable metric space. Then the families of second Baire class functions and of second Borel class functions from [0,1] to Y coincide if and only if for all finite sequences of nonempty open subsets of Y there exists a continuous function ϕ:[0,1] → Y such that for all i ≤ q.
Bibliography
- S. Banach, Oeuvres, Vol. 1, PWN, Warszawa, 1967, 207-217.
- L. G. Brown, Baire functions and extreme points, Amer. Math. Monthly 79 (1972), 1016-1018.
- R. Engelking, General Topology, PWN-Polish Scientific Publishers, Warszawa, 1977.
- W. G. Fleissner, An axiom for nonseparable Borel theory, Trans. Amer. Math. Soc. 251 (1979), 309-328.
- R. W. Hansell, Borel measurable mappings for nonseparable metric spaces, ibid. 161 (1971), 145-169.
- R. W. Hansell, On Borel mappings and Baire functions, ibid. 194 (1974), 195-211.
- R. W. Hansell, Extended Bochner measurable selectors, Math. Ann. 277 (1987), 79-94.
- R. W. Hansell, First class selectors for upper semi-continuous multifunctions, J. Funct. Anal. 75 (1987), 382-395.
- R. W. Hansell, First class functions with values in nonseparable spaces, in: Constantin Carathéodory: An International Tribute, T. M. Rassias (ed.), World Sci., Singapore, 1992, 461-475.
- K. Kuratowski, Topology, Vol. 1, Academic Press, New York, 1966.
- K. Kuratowski, Topology, Vol. 2, Academic Press, New York, 1968.
- M. Laczkowich, Baire 1 functions, Real Anal. Exchange 9 (1983-84), 15-28.
- C. A. Rogers, Functions of the first Baire class, J. London Math. Soc. (2) 37 (1988), 535-544.
- S. Rolewicz, On inversion of non-linear transformations, Studia Math. 17 (1958), 79-83.
Additional information
http://matwbn.icm.edu.pl/ksiazki/fm/fm143/fm14324.pdf