Quantitative decompositions of Lipschitz mappings into metric spaces
Abstract
We study the quantitative properties of Lipschitz mappings from Euclidean spaces into metric spaces. We prove that it is always possible to decompose the domain of such a mapping into pieces on which the mapping "behaves like a projection mapping" along with a "garbage set" that is arbitrarily small in an appropriate sense. Moreover, our control is quantitative, i.e., independent of both the particular mapping and the metric space it maps into. This improves a theorem of Azzam-Schul from the paper "Hard Sard", and answers a question left open in that paper. The proof uses ideas of quantitative differentiation, as well as a detailed study of how to supplement Lipschitz mappings by additional coordinates to form bi-Lipschitz mappings.
Keywords
Cite
@article{arxiv.2002.10318,
title = {Quantitative decompositions of Lipschitz mappings into metric spaces},
author = {Guy C. David and Raanan Schul},
journal= {arXiv preprint arXiv:2002.10318},
year = {2020}
}
Comments
53 pages, 1 figure. This version adds an important reference to a paper of David-Semmes that we previously overlooked. Remark 1.11 explains further