An $H^1$ multiplier theorem on anisotropic spaces
Yiyu Tang
TL;DR
The paper establishes an anisotropic version of the Sledd-Stegenga H^1 to L^p multiplier theorem for Hardy spaces $H^1_A$ associated with a dilation matrix $A$. It proves a sharp, two-regime criterion: for $1\le p<2$, a discrete $\ell^{2/(2-p)}$-type bound on $\mu$ over translated anisotropic rectangles, and for $2\le p<\infty$, a finite measure condition on anisotropic spheres $\{x: \rho_*(x)=b^k\}$. The sufficiency parts combine atomic decomposition, Fourier decay of atoms, and anisotropic covering arguments, while the necessity parts rely on Bochner–Riesz-type constructions and square-function techniques to extract necessary bounds. Together, these results extend the classical multiplier theory to anisotropic Hardy spaces, providing explicit, practically usable criteria for $H^1_A\to L^p$ boundedness in terms of the measure $\mu$ and the dilation geometry.
Abstract
A parallel result of (the classical) Sledd--Stegenga's $H^1\rightarrow L^1$ multiplier theorem was obtained on the $H^1$ space under the anisotropic settings. Based on the same technique, an $H^1\rightarrow L^p$ multiplier theorem is also proved for $1\leq p<\infty$.
