Abstract
We provide a simplification of Zahorski's argument showing that for every Lebesgue null $G_{\delta\sigma}$ subset $G$ of the line there is a Lipschitz function that is non-differentiable precisely at the points of $G$.
Citation
Thomas Fowler. David Preiss. "A Simple Proof of Zahorski’s Description of Non-Differentiability Sets of Lipschitz Functions." Real Anal. Exchange 34 (1) 127 - 138, 2008/2009.
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