Borel Sets and Hyperdegrees

@article{Friedman1973BorelSA,
  title={Borel Sets and Hyperdegrees},
  author={H. Friedman},
  journal={J. Symb. Log.},
  year={1973},
  volume={38},
  pages={405-409}
}
  • H. Friedman
  • Published 1973
  • Mathematics, Computer Science
  • J. Symb. Log.
This paper is concerned with the hyderdegrees of elements of uncountable Borel subsets of ω ω . The Borel subsets of ω ω are the so-called Δ 1 1 subsets of ω ω , which are the subsets of ω ω that are Δ 1 1 in some parameter f : ω → ω . The results of this paper were inspired by two earlier results about the hyperdegrees of elements of Σ 1 1 subsets of ω ω . The first is known as the Gandy basis theorem, and asserts that the collection of functions of strictly lower hyperdegree than the… Expand
7 Citations
Proof of a conjecture of Friedman
  • 12
  • PDF
On a Question of Jaegers
  • Highly Influenced
  • PDF
COMPLETELY ULTRAMETRIZABLE SPACES AND CONTINUOUS BIJECTIONS
  • 2014
  • 5
  • PDF
Luzin's (N) and randomness reflection
  • Highly Influenced
  • PDF
Π⁰₁ classes and degrees of theories
  • 355
  • PDF
Minimal covers and hyperdegrees
  • 26
  • PDF

References

SHOWING 1-3 OF 3 REFERENCES
Recursive pseudo-well-orderings
  • 118
  • PDF
A Minimal Pair of $\Pi^0_1$ Classes
  • 13