The extension problem for Sobolev spaces on the Heisenberg group

Abstract

We prove that if a domain $\Omega$ on the Heisenberg group \IH\sp{n} satisfies the $(\epsilon ,\delta)$ condition then there is a linear bounded extension operator ${\cal E}$ from {\cal L}\sp{k,p}(\Omega ) into {\cal L}\sp{k,p}(\IH\sp{n}) where $1\le k,\ 1\le p\le\infty$