A subelliptic Bourgain-Brezis inequality
arXiv:1210.1973
Abstract
We prove an approximation lemma on (stratified) homogeneous groups that allows one to approximate a function in the non-isotropic Sobolev space by functions, generalizing a result of Bourgain-Brezis \cite{MR2293957}. We then use this to obtain a Gagliardo-Nirenberg inequality for on the Heisenberg group .
44 pages