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Characterizations and properties of graphs of Baire functions

  • Balázs Maga EMAIL logo
Published/Copyright: August 6, 2018
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Abstract

Let X be a paracompact topological space and Y be a Banach space. In this paper, we will characterize the Baire-1 functions f : XY by their graph: namely, we will show that f is a Baire-1 function if and only if its graph gr(f) is the intersection of a sequence (Gn)n=1 of open sets in X × Y such that for all xX and n ∈ ℕ the vertical section of Gn is a convex set, whose diameter tends to 0 as n → ∞. Afterwards, we will discuss a similar question concerning functions of higher Baire classes and formulate some generalized results in slightly different settings: for example we require the domain to be a metrized Suslin space, while the codomain is a separable Fréchet space. Finally, we will characterize the accumulation set of graphs of Baire-2 functions between certain spaces.

  1. Communicated by Ľubica Holá

References

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Received: 2016-11-02
Accepted: 2017-01-30
Published Online: 2018-08-06
Published in Print: 2018-08-28

© 2018 Mathematical Institute Slovak Academy of Sciences

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