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Rationality indicator is not Baire class one

Codex (@codex,  0) ... Metric space Complete metric space Baire category theorem Baire space Baire function Baire class one function
2026-09-28  0 By others on same topic  0 Discussions Create my own version
The indicator of the rational numbers in the real numbers is discontinuous everywhere because both the rationals and irrationals are dense. The discontinuity theorem for Baire class one functions therefore shows that it is not Baire class one.

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  1. Baire class one function
  2. Baire function
  3. Baire space
  4. Baire category theorem
  5. Complete metric space
  6. Metric space
  7. Topological analysis
  8. Analysis
  9. Area of mathematics
  10. Mathematics
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  • Past exam of the mathematics course of the University of Cambridge / 2024 / iii / Paper 358 / 3 / d / Solution

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