共查询到19条相似文献,搜索用时 93 毫秒
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程立新 《应用泛函分析学报》2011,13(4):349-350,391
从泛函分析观点来看Lebesgue积分,使得Lebesgue积分可以用泛函分析最简单最基本的方法独立导出.基本做法是将Riemann对于区间[0,1]上的连续函数的积分看成连续函数空间C[0,1]上的连续线性泛函,再将它“自然”延拓到C[0,1]在积分范数意义下的完备化空间,而这个完备化空间正是Lebesgue可积函数空间L1[0,1]. 相似文献
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关于勒贝格积分的一个注记 总被引:2,自引:0,他引:2
陈晓雷 《数学的实践与认识》2002,32(6):1054-1056
本文给出了函数 f(x)的瑕积分绝对收敛时必定 Lebesgue可积的一种证明方法 相似文献
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f(x)为[0,1]上的Lebesgue可积函数,若它还在0的一个邻域内有界,则f(x^n)(n≥1)也在[0,1]上Lebesgue可积,其积分值的极限当f(x)为单调函数时收敛于f(0 0)。 相似文献
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总结Riemann积分的发展历史、基本思想及其各种推广,介绍Riemann积分的局限性和缺陷,以及由此推动产生Lebesgue积分的过程. 相似文献
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在抽象测度空间中,用可测集EK去逼近集E的办法,从函数f在E上的可测性去推f在E上的可积性,是判别函数可积性的一个新的重要命题,但[2]在证明这一命题时有误.本文作了更正,并从距离空间中的积分推广到抽象测度空间中的积分. 相似文献
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在偏微分方程Riemann解法和微分方程裂变思想的启发下,引入了微分方程乘子函数(解)和乘子解法的概念,系统地讨论了二阶线性微分方程的乘子可积性.得到了二阶线性微分方程乘子可积的条件以及Riceati方程可积的充分必要条件,并分别给出了二阶线性微分方程和Riccati方程在乘子解下的通积分. 相似文献
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U. B. Darji and M. J. Evans [1] showed previously that it is possible to obtain the integral of a Lebesgue integrable function
on the interval [0,1] via a Riemann type process, where one chooses the selected point in each partition interval using a
first-return algorithm based on a sequence {x
n} which is dense in [0,1]. Here we show that if the same is true for every rearrangement of {x
n}, then the function must be equal almost everywhere to a Riemann integrable function.
This revised version was published online in June 2006 with corrections to the Cover Date. 相似文献
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R. Witula等人在加额外限制条件下,得到了黎曼积分的强第二积分中值定理.本文在无额外限制条件下得到了相同的结论.同时利用连续函数在$L^p[a,b]~(p \geq 1)$空间的稠密性,将强第二积分中值定理推广到$L^p[a,b]$空间. 相似文献
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On existence of integrable solutions of a functional integral equation under Carathéodory conditions
We study the solvability of a functional integral equation in the space of Lebesgue integrable functions on an unbounded interval. Using the conjunction of the technique of measures of weak noncompactness with the classical Schauder fixed point principle we show that the equation in question is solvable in the mentioned function space. Our existence result is obtained under the assumption that functions involved in the investigated functional integral equation satisfy Carathéodory conditions. Moreover, that result generalizes several ones obtained earlier in many research papers and monographs. 相似文献
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In this paper we randomize in a particular way the sequence of partitions based on which the random Riemann sums are defined
for a Lebesgue integrable function f on (0, 1). Convergence of such sums to the Lebesgue integral of f is investigated. 相似文献
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In general, Banach space-valued Riemann integrable functions defined on [0, 1] (equipped with the Lebesgue measure) need not be weakly continuous almost everywhere. A Banach space is said to have the weak Lebesgue property if every Riemann integrable function taking values in it is weakly continuous almost everywhere. In this paper we discuss this property for the Banach space LX^1 of all Bochner integrable functions from [0, 1] to the Banach space X. We show that LX^1 has the weak Lebesgue property whenever X has the Radon-Nikodym property and X* is separable. This generalizes the result by Chonghu Wang and Kang Wan [Rocky Mountain J. Math., 31(2), 697-703 (2001)] that L^1[0, 1] has the weak Lebesgue property. 相似文献
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In this paper we introduce and investigate a Henstock-Kurzweil-type integral for Riesz-space-valued functions defined on (not necessarily bounded) subintervals of the extended real line. We prove some basic properties, among them the fact that our integral contains under suitable hypothesis the generalized Riemann integral and that every simple function which vanishes outside of a set of finite Lebesgue measure is integrable according to our definition, and in this case our integral coincides with the usual one. 相似文献
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Jack Grahl 《Journal of Mathematical Analysis and Applications》2008,340(1):358-365
We construct an integral of a measurable real function using randomly chosen Riemann sums and show that it converges in probability to the Lebesgue integral where this exists. We then prove some conditions for the almost sure convergence of this integral. 相似文献