## The set of continuous functions with everywhere convergent Fourier series

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- by M. Ajtai and A. S. Kechris PDF
- Trans. Amer. Math. Soc.
**302**(1987), 207-221 Request permission

## Abstract:

This paper deals with the descriptive set theoretic properties of the class $\operatorname {EC}$ of continuous functions with everywhere convergent Fourier series. It is shown that this set is a complete coanalytic set in $C(T)$. A natural coanalytic rank function on $\operatorname {EC}$ is studied that assigns to each $f \in \operatorname {EC}$ a countable ordinal number, which measures the "complexity" of the convergence of the Fourier series of $f$. It is shown that there exist functions in $\operatorname {EC}$ (in fact even differentiable ones) which have arbitrarily large countable rank, so that this provides a proper hierarchy on $\operatorname {EC}$ with ${\omega _1}$ distinct levels.## References

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## Additional Information

- © Copyright 1987 American Mathematical Society
- Journal: Trans. Amer. Math. Soc.
**302**(1987), 207-221 - MSC: Primary 04A15; Secondary 26A21, 42A20
- DOI: https://doi.org/10.1090/S0002-9947-1987-0887506-4
- MathSciNet review: 887506