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arXiv 2006.16871math.FAmath.CAmath.CV
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奇多项式逼近奇函数的失效

Failure of Approximation of Odd Functions by Odd Polynomials

Javad Mashreghi, Pierre-Olivier Parisé, Thomas Ransford

摘要:

构造了单位圆盘上的Hilbert全纯函数空间$H$,使得多项式在$H$中稠密,而奇多项式在$H$中的奇函数中不稠密.因此,在$H$中存在一个函数$f$,它位于其泰勒部分和$s_n(f)$的闭合线性跨度之外,因此它不能通过应用于$s_n(f)$的任何三角求和方法来近似。我们还表明,存在一个功能$f$在$H$,位于其径向扩张$f_r, ~r<1$的封闭的线性跨度之外。

英文摘要:

We construct a Hilbert holomorphic function space $H$ on the unit disk such that the polynomials are dense in $H$, but the odd polynomials are not dense in the odd functions in $H$. As a consequence, there exists a function $f$ in $H$ that lies outside the closed linear span of its Taylor partial sums $s_n(f)$, so it cannot be approximated by any triangular summability method applied to the $s_n(f)$. We also show that there exists a function $f$ in $H$ that lies outside the closed linear span of its radial dilates $f_r, ~r<1$.

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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