We study, in $L^{1}(\R^n;γ)$ with respect to the gaussian measure, non-tangential maximal functions and conical square functions associated with the Ornstein-Uhlenbeck operator by developing a set of techniques which allow us, to some extent, to compensate for the non-doubling character of the gaussian measure. The main result asserts that conical square functions can be controlled in $L^1$-norm by non-tangential maximal functions. Along the way we prove a change of aperture result for the latter. This complements recent results on gaussian Hardy spaces due to Mauceri and Meda.
Atomic and Maximal Function Characterizations of Musielak-Orlicz-Hardy Spaces Associated to Non-negative Self-adjoint Operators on Spaces of Homogeneous Type
Real-Variable Characterizations of Local Hardy Spaces on Spaces of Homogeneous Type
设$(X,d,μ)$是齐型空间,其上维数为$μ$,在R意义下. R. Coifman和G.外斯设$η$为P. Auscher和T.海托宁利用局部极大函数引入了局部Hardy空间$h^{*,p}(X)$,并利用局部径向极大函数、局部非切极大函数、局部原子和局部Littlewood-Paley函数刻画了$h^{*,p}(X)$.进一步建立了整体Hardy空间与局部Hardy空间之间的关系。最后,得到了$h^{*,p}(X)$的有限原子刻画.作为应用,给出了当$p\in(ω/(ω+η),1)$时$h^{*,p}(X)$的对偶空间,进一步完善了G. Dafni和H. Yue关于$h^{*,1}(X)$的对偶空间.本文还回答了R. R. Coifman和G. Weiss关于任何额外的几何假设的不必要性,除了当$μ(X)<\infty$时$H^1_{\mathrm{cw}}(X)$的径向极大函数特征化的加倍条件。
Hardy Spaces Associated with Ball Quasi-Banach Function Spaces on Spaces of Homogeneous Type: Characterizations of Maximal Functions, Decompositions, and Dual Spaces
A Complete Real-Variable Theory of Hardy Spaces on Spaces of Homogeneous Type
设$(X,d,μ)$是齐型空间,其上维数为$ω$,在R意义下. R. Coifman和G.外斯设$X$是P. Auscher和T.海托宁本文对Coifman和Weiss引入的原子Hardy空间$H_{\mathrm{cw}}^p(X)$,分别用巨极大函数、径向极大函数、非切极大函数、各种Littlewood-Paley函数和小波函数建立了它们的各种实变量刻画.这完全回答了R. R. Coifman和G. Weiss通过表明没有任何附加的(几何)条件是必要的,以保证径向最大函数表征的$H_{\mathrm{cw}}^1(X)$,甚至$H_{\mathrm{cw}}^p(X)$与$p$如上所述。作为应用,得到了$H^p_{\mathrm{cw}}(X)$的有限原子刻画,从而进一步导出了次线性算子在$H^p_{\mathrm{cw}}(X)$上有界的一些判据.与已有结果相比,本文的创新之处在于没有假设$μ$满足反向加倍条件,$d$只是一个拟度量,而且$p\in(ω/(ω+η),1]$的取值范围$p\in(ω/(ω+η),1]$是自然的、最优的.