文摘
We prove the density of polyhedral partitions in the set of finite Caccioppoli partitions. Precisely, given a decomposition u of a bounded Lipschitz set \(\Omega \subset {\mathbb {R}}^n\) into finitely many subsets of finite perimeter and \({\varepsilon }>0\), we prove that u is \({\varepsilon }\)-close to a small deformation of a polyhedral decomposition \(v_{\varepsilon }\), in the sense that there is a \(C^1\) diffeomorphism \(f_{\varepsilon }:{\mathbb {R}}^n\rightarrow {\mathbb {R}}^n\) which is \({\varepsilon }\)-close to the identity and such that \(u\circ f_{\varepsilon }-v_{\varepsilon }\) is \({\varepsilon }\)-small in the strong BV norm. This implies that the energy of u is close to that of \(v_{\varepsilon }\) for a large class of energies defined on partitions.