Estimates for the maximal singular integral in terms of the singular integral: the case of even kernels
Estimates for the maximal singular integral in terms of the singular integral: the case of even kernels
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根据奇异积分估计最大奇异积分:偶核的情况
DOI:
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发表时间:
2011
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影响因子:
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通讯作者:
Juan Verdera Melenchón
中科院分区:
文献类型:
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作者:
Joan Mateu Bennassar;Joan Orobitg i Huguet;Juan Verdera Melenchón
Let T be a smooth homogeneous Calder on-Zygmund singular integral operator in R n . In this paper we study the problem of controlling the maximal singular integral T ? f by the singular integral Tf. The most basic form of control one may consider is the estimate of the L 2 (R n ) norm of T ? f by a constant times the L 2 (R n ) norm of Tf. We show that if T is an even higher order Riesz transform, then one has the stronger pointwise inequality T ? f(x) C M(Tf)(x), where C is a constant and M is the Hardy-Littlewood maximal operator. We prove that the L 2 estimate of T ? by T is equivalent, for even smooth homogeneous Calder on-Zygmund operators, to the pointwise inequality between T ? and M(T ). Our main result characterizes the L 2 and pointwise inequalities in terms of an algebraic condition expressed in terms of the kernel ( x) jxjn of T , where is an