We add to the literature the following observation. If μ is a singular measure on R which assigns measure zero to every porous set and f : R → R is a Lipschitz function which is non-differentiable μ-a.e., then for every C function g : R → R it holds μ{x ∈ Rn : f(x) = g(x)} = 0. In other words the Lusin type approximation property of Lipschitz functions with C functions does not hold with respec...

Let X X be a compact metric space and let alttext="v"> v encoding="application/x-tex">v sub-additive ...

We establish new approximation results in the sense of Lusin for Sobolev functions f with |∇f|∈Llog⁡L on infinite-dimensional spaces equipped Gaussian measures. The proof relies some pointwise estimate approximations based corresponding semigroup which can be independent interest.

In this paper, we address the equivalence of the analytic and probabilistic notions of harmonicity in the context of general symmetric Hunt processes on locally compact separable metric spaces. Extensions to general symmetric right processes on Lusin spaces including infinite dimensional spaces are mentioned at the end of this paper. AMS 2000 Mathematics Subject Classification: Primary 60J45, 3...

Abstract We study the behavior of Lipschitz functions on intrinsic $C^1$ submanifolds Heisenberg groups: our main result is their almost everywhere tangential Pansu differentiability. also provide two applications: a Lusin-type approximation ${\mathbb {H}}$-rectifiable sets and coarea formula that completes program started in [18].