Displaying similar documents to “A reduction of the Nielsen fixed point theorem for symmetric product maps to the Lefschetz theorem”

Extensions of Borel Measurable Maps and Ranges of Borel Bimeasurable Maps

Petr Holický (2004)

Bulletin of the Polish Academy of Sciences. Mathematics

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We prove an abstract version of the Kuratowski extension theorem for Borel measurable maps of a given class. It enables us to deduce and improve its nonseparable version due to Hansell. We also study the ranges of not necessarily injective Borel bimeasurable maps f and show that some control on the relative classes of preimages and images of Borel sets under f enables one to get a bound on the absolute class of the range of f. This seems to be of some interest even within separable spaces. ...