Dunkl paraproducts and fractional Leibniz rules for the Dunkl Laplacian

Abstract

We establish fractional Leibniz rules for the Dunkl Laplacian $Δ_k$ of the form $$\|(-Δ_k)^s(fg)\|_{L^p(dμ_k)} \lesssim \|(-Δ_k)^s f\|_{L^{p_1}(dμ_k)} \|g\|_{L^{p_2}(dμ_k)} + \|f\|_{L^{p_1}(dμ_k)} \|(-Δ_k)^s g\|_{L^{p_2}(dμ_k)}.$$ Our approach relies on adapting the classical paraproduct decomposition to the Dunkl setting. In the process, we develop several new auxiliary results. Specifically, we show that for a Schwartz function $f$, the function $(-Δ_k)^s f$ satisfies a pointwise decay estimate; we establish a version of almost orthogonality estimates adapted to the Dunkl framework; and we investigate the boundedness of Dunkl paraproduct operators on the Lebesgue spaces.