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Let $Omega$ be homogeneous of degree zero, have mean value zero and integrable on the unit sphere, and $mu_{Omega}$ be the higher-dimensional Marcinkiewicz integral defined by $$mu_Omega(f)(x)= Big(int_0^inftyBig|int_{|x-y|leq t}frac{Omega(x-y)}{|x-y|^{n-1}}f(y)dyBig|^2frac{dt}{t^3}Big)^{1/2}. $$ In this paper, the authors establish a bilinear sparse domination for $mu_{Omega}$ under the assumption $Omegain L^{infty}(S^{n-1})$. As applications, some quantitative weighted bounds for $mu_{Omega}$ are obtained.
We present a general approach to sparse domination based on single-scale $L^p$-improving as a key property. The results are formulated in the setting of metric spaces of homogeneous type and avoid completely the use of dyadic-probabilistic techniques
We prove endpoint-type sparse bounds for Walsh-Fourier Marcinkiewicz multipliers and Littlewood-Paley square functions. These results are motivated by conjectures of Lerner in the Fourier setting. As a corollary, we obtain novel quantitative weighted
The purpose of this paper is to study the sparse bound of the operator of the form $f mapsto psi(x) int f(gamma_t(x))K(t)dt$, where $gamma_t(x)$ is a $C^infty$ function defined on a neighborhood of the origin in $(x, t) in mathbb R^n times mathbb R^k
By a reduction method, the limiting weak-type behaviors of factional maximal operators and fractional integrals are established without any smoothness assumption on the kernel, which essentially improve and extend previous results. As a byproduct, we
Let $Omega$ be homogeneous of degree zero and have mean value zero on the unit sphere ${S}^{d-1}$, $T_{Omega}$ be the homogeneous singular integral operator with kernel $frac{Omega(x)}{|x|^d}$ and $T_{Omega,,b}$ be the commutator of $T_{Omega}$ with