Differentiation properties of class L1([0,1)2) with respect to two different bases ofrectangles

被引:0
|
作者
Hirayama, Michihiro [1 ]
Karagulyan, Davit [2 ]
机构
[1] Univ Tsukuba, Dept Math, Tsukuba, Ibaraki 3058571, Japan
[2] KTH Royal Inst Technol, S-10044 Stockholm, Sweden
基金
日本学术振兴会;
关键词
Differentiation of integrals; Differentiation bases; Rare bases; Random translations;
D O I
10.1007/s44146-024-00127-9
中图分类号
O1 [数学];
学科分类号
0701 ; 070101 ;
摘要
The Lebesgue differentiation theorem claims that the integralaverages of f is an element of L-1([0,1)(2)) with respect to the family of axis-parallelsquaresconverge almost everywhere on [0,1)2. On the other hand, it isa well known result by Saks that there exist a function f is an element of L-1([0,1)(2)) such that its integral averages with respect to the family of axis-parallelrectanglesdiverge everywhere on [0,1)2. In this paper, we address thefollowing question: assume we have two different collections of rectan-gles; under which conditions does there exist a function f is an element of L-1([0,1)2) so that its integral averages converge with respect to one collection anddiverge with respect to another? More specifically, let C, D subset of(0,1]and consider rectangles with side lengths respectively in C and D. Weshow that if the sets C and Doccasionally become sufficiently "far"from each other, then such a function can be constructed. We also showthat in the class of positive functions our condition is necessary for sucha function to exist.
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页数:32
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