Lipschitz functions on submanifolds in Heisenberg groups
arXiv:2107.00515
Abstract
We study the behavior of Lipschitz functions on intrinsic submanifolds of Heisenberg groups: our main result is their almost everywhere tangential Pansu differentiability. We also provide two applications: a Lusin-type approximation of Lipschitz functions on $\HH$-rectifiable sets, and a coarea formula on $\HH$-rectifiable sets that completes the program started in~\cite{JNGV}.
16 pages