On rough traces of BV functions

Abstract

In metric measure spaces, we study boundary traces of BV functions in domains equipped with a doubling measure and supporting a Poincar\'e inequality, but possibly having a very large and irregular boundary. We show that the trace exists in the ordinary sense in a certain part of the boundary, and that this part is sufficient to determine the integrability of the rough trace, as well as the possibility of zero extending the function to the whole space as a BV function.