English

A characterization of two weight norm inequality for Littlewood-Paley $g_{\lambda}^{*}$-function

Classical Analysis and ODEs 2018-05-15 v2

Abstract

Let n2n\ge 2 and gλg_{\lambda}^{*} be the well-known high dimensional Littlewood-Paley function which was defined and studied by E. M. Stein, \begin{align*} g_{\lambda}^{*}(f)(x) =\bigg(\iint_{\mathbb R^{n+1}_{+}} \Big(\frac{t}{t+|x-y|}\Big)^{n\lambda} |\nabla P_tf(y,t)|^2 \frac{dy dt}{t^{n-1}}\bigg)^{1/2}, \ \quad \lambda > 1, \end{align*} where Ptf(y,t)=ptf(y)P_tf(y,t)=p_t*f(y), pt(y)=tnp(y/t)p_t(y)=t^{-n}p(y/t) and p(x)=(1+x2)(n+1)/2p(x) = (1+|x|^2)^{-(n+1)/2}, =(y1,,yn,t)\nabla =(\frac{\partial}{\partial y_1},\ldots,\frac{\partial}{\partial y_n},\frac{\partial}{\partial t}). In this paper, we give a characterization of two-weight norm inequality for gλg_{\lambda}^{*}-function. We show that, gλ(fσ)L2(w)fL2(σ)\big\| g_{\lambda}^{*}(f \sigma) \big\|_{L^2(w)} \lesssim \big\| f \big\|_{L^2(\sigma)} if and only if the two-weight Muchenhoupt A2A_2 condition holds, and a testing condition holds : \begin{align*} \sup_{Q : cubes \ in \mathbb R^n} \frac{1}{\sigma(Q)} \int_{\mathbb R^n} \iint_{\widehat{Q}} \Big(\frac{t}{t+|x-y|}\Big)^{n\lambda}|\nabla P_t(\mathbf{1}_Q \sigma)(y,t)|^2 \frac{w dx dt}{t^{n-1}} dy < \infty, \end{align*} where Q^\widehat{Q} is the Carleson box over QQ and (w,σ)(w, \sigma) is a pair of weights. We actually prove this characterization for gλg_{\lambda}^{*}-function associated with more general fractional Poisson kernel pα(x)=(1+x2)(n+α)/2p^\alpha(x) = (1+|x|^2)^{-{(n+\alpha)}/{2}}. Moreover, the corresponding results for intrinsic gλg_{\lambda}^*-function are also presented.

Keywords

Cite

@article{arxiv.1504.07850,
  title  = {A characterization of two weight norm inequality for Littlewood-Paley $g_{\lambda}^{*}$-function},
  author = {Mingming Cao and Kangwei Li and Qingying Xue},
  journal= {arXiv preprint arXiv:1504.07850},
  year   = {2018}
}

Comments

21 pages, to appear in Journal of Geometric Analysis

R2 v1 2026-06-22T09:25:00.494Z