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arXiv 0711.0679math.CA
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连续函数的限制

Restrictions of continuous functions

Jean-Pierre Kahane, Yitzhak Katznelson

摘要:

给定一个在[0,1]上的连续实值函数和一个闭子集E \subset [0,1],我们用f E表示f对E的限制,也就是说,只在E上定义的函数在E >的每一点上取与f相同的值。限制f E通常比f“表现更好”。它可能有界变差,当f没有时,它可能有一个比f更好的连续模,当f不是时,它可能是单调的,等等。所有这些显然取决于f和E,我们在这里讨论的问题是关于存在性的,对于每个f,或某类中的每个f,“实质”集合E,使得f E有界全变差,是单调的,或者满足给定的连续模。我们使用的“实体”概念是豪斯多夫或闵可夫斯基维数。

英文摘要:

Given a continuous real-valued function on [0, 1], and a closed subset E \subset [0, 1] we denote by f E the restriction of f to E, that is, the function defined only on E that takes the same values as f at every point of E >. The restriction f E will typically be "better behaved" than f . It may have bounded variation when f doesn't, it may have a better modulus of continuity than f, it may be monotone when f is not, etc. All this clearly depends on f and on E, and the questions that we discuss here are about the existence, for every f, or every f in some class, of "substantial" sets E such that f E has bounded total variation, is monotone, or satisfies a given modulus of continuity. The notion of "substantial" that we use is that of either Hausdorff or Minkowski dimensions.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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