Metric characterization of pure unrectifiability.

Abstract

We show that an analytic subset of the finite dimensional Euclidean space $\real^\dimens$ is purely unrectifiable if and only if the image of any of its compact subsets under every \locquo{} function is a Lebesgue null. We also construct purely unrectifiable compact sets of Hausdorff dimension greater than $1$ which are necessarily sent to finite sets by \locquo{} functions.