A note on maximal singular integrals with rough kernels

In this note we study the maximal singular integral operators associated with a homogeneous mapping with rough kernels as well as the corresponding maximal operators. The boundedness and continuity on the Lebesgue spaces, Triebel–Lizorkin spaces, and Besov spaces are established for the above operators with rough kernels in $H^{1}({\mathrm{S}}^{n-1})$ H 1 ( S n − 1 ) , which complement some recent developments related to rough maximal singular integrals.

An Endpoint Estimate for Rough Maximal Singular Integrals

We study the rough maximal singular integral $$T^{\#}_\Omega\big(\,f\big)\big(x\big)=\sup_{\varepsilon>0} \left| \int_{\mathbb{R}^{n}\setminus B(0,\varepsilon)}|y|^{-n} \Omega(y/|y|)\,f(x-y) \mathrm{d}y\right|,$$where $\Omega$ is a function in $L^\infty (\mathbb{S}^{n-1})$ with vanishing integral. It is well known that the operator is bounded on $L^p$ for $1<p<\infty ,$ but it is an open question whether it is of the weak type 1-1. We show that $T^{\#}_\Omega$ is bounded from $L(\log \log L)^{2+\varepsilon }$ to $L^{1,\infty }$ locally.

BOUNDEDNESS OF SINGULAR INTEGRALS AND MAXIMAL SINGULAR INTEGRALS ON TRIEBEL–LIZORKIN SPACES

In this paper, assuming Ω ∈ H1(Sn-1), we prove that the singular integral TΩ and the maximal singular integral [Formula: see text] are all bounded on Triebel–Lizorkin spaces, homogeneous or inhomogeneous.