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arXiv 1604.08643math.CAcs.NAmath.NA
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高阶修正梯形法则在勒贝格空间和亚历山德罗夫空间中的应用

Higher order corrected trapezoidal rules in Lebesgue and Alexiewicz spaces

University of the Fraser Valley(弗雷泽河谷大学)

Erik Talvila

AI总结:

本文研究了在勒贝格和亚历山德罗夫空间中高阶修正梯形法则的积分公式,通过积分分部得到误差估计,并证明了当f为多项式时的精确性。

摘要:

若函数f: [a,b]→R满足f的n阶导数可积,则积分分部可得公式:∫_a^b f(x)dx = [(-1)^n /n!] Σ_{k=0}^{n-1} (-1)^{n-k-1} [ϕ_n^{(n-k-1)}(a)f^{(k)}(a) - ϕ_n^{(n-k-1)}(b)f^{(k)}(b)] + E_n(f),其中ϕ_n是次数为n的monic多项式,误差由E_n(f) = [(-1)^n /n!] ∫_a^b f^{(n)}(x)ϕ_n(x)dx给出。这为∫_a^b f(x)dx提供了求积公式。多项式ϕ_n被选择以优化误差估计,假设f^{(n)} ∈ L^p([a,b]) (1 ≤ p ≤ ∞) 或在分布学或Henstock-Kurzweil意义上可积。获得了精确的误差估计。证明当f为次数至多为n-1的多项式时,该公式对所有ϕ_n精确。若ϕ_n为Legendre多项式,则该公式对f为次数至多为2n-1的多项式精确。

英文摘要:

If $f\!:\![a,b]\to\R$ such that $f^{(n)}$ is integrable then integration by parts gives the formula \begin{align*} &\intab f(x)\,dx = &\frac{(-1)^n}{n!}\sum_{k=0}^{n-1}(-1)^{n-k-1}\left[ ϕ_n^{(n-k-1)}(a)f^{(k)}(a)- ϕ_n^{(n-k-1)}(b)f^{(k)}(b)\right] +E_n(f), \end{align*} where $ϕ_n$ is a monic polynomial of degree $n$ and the error is given by $E_n(f)=\frac{(-1)^n}{n!}\int_a^b f^{(n)}(x)ϕ_n(x)\,dx$. This then gives a quadrature formula for $\int_a^bf(x)\,dx$. The polynomial $ϕ_n$ is chosen to optimize the error estimate under the assumption that $f^{(n)}\in L^p([a,b])$ for some $1\leq p\leq\infty$ or if $f^{(n)}$ is integrable in the distributional or Henstock--Kurzweil sense. Sharp error estimates are obtained. It is shown that this formula is exact for all such $ϕ_n$ if $f$ is a polynomial of degree at most $n-1$. If $ϕ_n$ is a Legendre polynomial then the formula is exact for $f$ a polynomial of degree at most $2n-1$.

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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