author={Linda Brown Westrick},
  journal={The Journal of Symbolic Logic},
  pages={240 - 265}
  • L. Westrick
  • Published 2014
  • Mathematics, Computer Science
  • The Journal of Symbolic Logic
Abstract We examine the computable part of the differentiability hierarchy defined by Kechris and Woodin. In that hierarchy, the rank of a differentiable function is an ordinal less than ${\omega _1}$ which measures how complex it is to verify differentiability for that function. We show that for each recursive ordinal $\alpha > 0$ , the set of Turing indices of $C[0,1]$ functions that are differentiable with rank at most α is ${{\rm{\Pi }}_{2\alpha + 1}}$ -complete. This result is expressed in… Expand
4 Citations
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An Effective Analysis of the Denjoy Rank
  • L. Westrick
  • Computer Science, Mathematics
  • Notre Dame J. Formal Log.
  • 2020
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