Intrinsic perimeter, compactness and Poincaré inequality for SBV functions in Carnot-Carathéodory spaces
Marco Di Marco
TL;DR
The paper develops sub-Riemannian analogues of classical SBV theory in equiregular Carnot–Carathéodory spaces by introducing an intrinsic perimeter measure for countably X-rectifiable sets and assuming property $\mathcal{R}$. It proves a compactness theorem for SBV$_X$ functions and a Poincaré inequality, expressing the derivative $D_Xu$ in terms of the approximate gradient and the jump contribution via the intrinsic perimeter $\mathcal{P}^X_{\mathcal{J}_u}$. The core ideas combine the intrinsic perimeter with a chain-rule-based compactness argument and an isoperimetric-based Poincaré framework, enabling rigorous control of both the absolutely continuous and jump parts. These results establish sub-Riemannian SBV theory with tools such as the coarea formula and CC-space isoperimetry, and pave the way for variational and geometric analysis in CC settings.
Abstract
By introducing an intrinsic perimeter measure for intrinsic countably rectifiable sets, we prove a compactness result and a Poincaré inequality for special functions with bounded variation in equiregular Carnot-Carathéodory spaces which satisfy an additional natural assumption, called property $\mathcal R$.
