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Typical Lipschitz images of rectifiable metric spaces. (English) Zbl 07840486

Summary: This article studies typical 1-Lipschitz images of \(n\)-rectifiable metric spaces \(E\) into \(\mathbb{R}^m\) for \(m\geq n\). For example, if \(E\subset\mathbb{R}^k\), we show that the Jacobian of such a typical 1-Lipschitz map equals 1 \(\mathcal{H}^n\)-almost everywhere and, if \(m>n\), preserves the Hausdorff measure of \(E\). In general, we provide sufficient conditions, in terms of the tangent norms of \(E\), for when a typical 1-Lipschitz map preserves the Hausdorff measure of \(E\), up to some constant multiple. Almost optimal results for strongly \(n\)-rectifiable metric spaces are obtained. On the other hand, for any norm \(\vert\,{\cdot}\,\vert\) on \(\mathbb{R}^m\), we show that, in the space of 1-Lipschitz functions from \(([-1,1]^n,\vert\,{\cdot}\,\vert_{\infty})\) to \((\mathbb{R}^m,\vert\,{\cdot}\,\vert)\), the \(\mathcal{H}^n\)-measure of a typical image is not bounded below by any \(\Delta>0\).

MSC:

28A75 Length, area, volume, other geometric measure theory
28A78 Hausdorff and packing measures
49Q15 Geometric measure and integration theory, integral and normal currents in optimization
46B80 Nonlinear classification of Banach spaces; nonlinear quotients
53C23 Global geometric and topological methods (à la Gromov); differential geometric analysis on metric spaces

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