Embedding derivatives and derivative Area operators of Hardy spaces into Lebesgue spaces

We characterize the compactness of embedding derivatives from Hardy space $H^p$ into Lebesgue space $L^q(\mu )$. We also completely characterize the boundedness and compactness of derivative area operators from $H^p$ into $L^q({\mathbb{S}}_n)$, $0<p,q<\mathrm{\infty }$. Some of the tools used in the proof of the one-dimensional case are not available in higher dimensions, such as the strong factorization of Hardy spaces. Therefore, we need the theory of tent spaces which was established by Coifman, Mayer and Stein in 1985.