A compact null set containing a differentiability point of every Lipschitz function
arXiv:0804.4576 · doi:10.1007/s00208-010-0613-4
Abstract
We prove that in a Euclidean space of dimension at least two, there exists a compact set of Lebesgue measure zero such that any real-valued Lipschitz function defined on the space is differentiable at some point in the set. Such a set is constructed explicitly.
28 pages; minor modifications throughout; Lemma 4.2 is proved for general Banach space rather than for Hilbert space