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Asymptotic Behaviors of Hankelians, Whose Entries Involve Regularly- or Rapidly-Varying Functions, as the Variable Tends to +∞. Part I
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作者 Antonio Granata 《Advances in Pure Mathematics》 2024年第11期817-858,共42页
The rich literature concerning “asymptotic behavior of Hankel determinants” concerns the behavior, as the order n tends to ∞, of Hankel determinants whose entries are numbers, e.g., with a combinatorial interest or... The rich literature concerning “asymptotic behavior of Hankel determinants” concerns the behavior, as the order n tends to ∞, of Hankel determinants whose entries are numbers, e.g., with a combinatorial interest or arising as values of special classes of functions. Such determinants are numbers depending on n, playing roles in number theory, combinatorics, random matrices and the like;and mathematicians in the involved fields have been interested in their asymptotic behaviors as n goes to ∞, as previously mentioned, with no single exception to the author’s knowledge. The study carried on in the present paper treats an altogether different situation as suggested by the specification in the title “as the variable tends to +∞”. We deal with those types of Hankel determinants (purposely called Hankelians) which are special cases of Wronskians and, continuing our work on the asymptotics of Wronskians, we study the asymptotic behaviors of n-order Hankelians, whose entries involve either regularly- or rapidly-varying functions, when the variable tends to +∞. As in the study of Wronskians, the treatment of this case also needs the whole apparatus of the theory of higher-order types of asymptotic variation, but the most demanding results are not automatic corollaries of the general theory. In fact, in the study of generic Wronskians (study motivated by applications to asymptotic expansions), the entries were required to belong to one of the classes of “higher-order regular or rapid variation”;on the contrary, in the case of Hankelians, we are confronted with functions whose logarithms are either “regularly- or rapidly-varying functions”, roughly classifiable as “ultrarapidly-varying functions”, and the study requires both special devices and a number of preliminary lemmas about products and linear combinations of functions in the mentioned classes. 展开更多
关键词 asymptotic Behaviors of Hankelians asymptotic expansions in the real domain Regularly- Rapidly- and Exponentially-Varying Functions of Higher Order
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深水时域格林函数的实用数值计算 被引量:15
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作者 申亮 朱仁传 +1 位作者 缪国平 刘应中 《水动力学研究与进展(A辑)》 CSCD 北大核心 2007年第3期380-386,共7页
如何精确而又快速地计算时域格林函数及其导数是求解船舶水动力问题的关键。论文基于Bessel函数的性质推导了深水格林函数及其导数所满足的常微分方程,提出了结合求解常微分方程的节点制表、节点间插值的快速计算格林函数的方法。数值... 如何精确而又快速地计算时域格林函数及其导数是求解船舶水动力问题的关键。论文基于Bessel函数的性质推导了深水格林函数及其导数所满足的常微分方程,提出了结合求解常微分方程的节点制表、节点间插值的快速计算格林函数的方法。数值计算表明该计算方法克服前人节点制表节点间插值计算方法的缺点,提高了格林函数的计算效率和数值精度。 展开更多
关键词 时域格林函数 级数展开 渐近表达 常微分方程 插值
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时域有限水深格林函数及其导数的数值计算 被引量:4
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作者 戴愚志 余建星 郭海涛 《船舶力学》 EI 北大核心 2006年第1期15-21,共7页
精确快速地求取有限水深格林函数及它的导数是应用时域法求解有限水深水动力学问题的关键。通过对有限水深格林函数在不同区域渐近特性的分析,给出了使用多维Chebyshev多项式和渐近展开式快速近似计算有限水深格林函数及它的导数的方法... 精确快速地求取有限水深格林函数及它的导数是应用时域法求解有限水深水动力学问题的关键。通过对有限水深格林函数在不同区域渐近特性的分析,给出了使用多维Chebyshev多项式和渐近展开式快速近似计算有限水深格林函数及它的导数的方法。近似方法与直接积分方法的比较表明近似方法的计算工作量大幅减少,可以给出足够精度的计算结果。 展开更多
关键词 格林函数 时域 有限水深 CHEBYSHEV多项式 渐近展开式
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渐近非扩张映象的具误差的粘性迭代逼近 被引量:5
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作者 胡洪萍 王琳琳 梁晓茹 《黑龙江大学自然科学学报》 CAS 北大核心 2010年第5期573-576,581,共5页
近几年,国内外学者利用一步粘性序列,得到了Banach空间中强收敛到非扩张映像不动点的条件。而非扩张映像一定是渐近非扩张映像。引入渐近非扩张映象的具误差的两步粘性迭代序列,采用迭代和不等式技巧和方法,得出了Banach空间中渐近非扩... 近几年,国内外学者利用一步粘性序列,得到了Banach空间中强收敛到非扩张映像不动点的条件。而非扩张映像一定是渐近非扩张映像。引入渐近非扩张映象的具误差的两步粘性迭代序列,采用迭代和不等式技巧和方法,得出了Banach空间中渐近非扩张映象的具误差的两步粘性迭代序列的收敛性及强收敛于其不动点的条件。进而改进和推广了最新的结果。 展开更多
关键词 实BANACH空间 渐近非扩张映象 具误差的粘性迭代序列 不动点
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一种改进的吸引域估计的方法
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作者 金德泉 禹磊 《科技视界》 2018年第6期187-188,共2页
在考察具有渐近稳定平衡点的非线性动力系统的时候,其吸引域范围是判断系统稳定性的一类重要指标.利用最优Lyapunovh函数法,可以得到一大类非线性动力系统所对应的Lyapunov函数,并利用该函数对吸引域范围进行估计.基于最优最优Lyapunov... 在考察具有渐近稳定平衡点的非线性动力系统的时候,其吸引域范围是判断系统稳定性的一类重要指标.利用最优Lyapunovh函数法,可以得到一大类非线性动力系统所对应的Lyapunov函数,并利用该函数对吸引域范围进行估计.基于最优最优Lyapunov函数,通过对原吸引域估计方法进行改进,可以显著提高估计的准确性,得到更好估计结果,并通过数值实验证明了这一点。 展开更多
关键词 渐近稳定平衡点 吸引域 迭代扩展法
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Spectral analysis and numerical simulation for second order elliptic operator with highly oscillating coefficients in perforated domains with a periodic structure 被引量:2
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作者 曹礼群 崔俊芝 +1 位作者 诸德超 罗剑兰 《Science China Mathematics》 SCIE 2002年第12期1588-1602,共15页
This paper discusses the spectral properties and numerical simulation for the second order elliptic operators with rapidly oscillating coefficients in the domains which may contain small cavities distributed periodica... This paper discusses the spectral properties and numerical simulation for the second order elliptic operators with rapidly oscillating coefficients in the domains which may contain small cavities distributed periodically with period ε. A multiscale asymptotic analysis formula for this problem is obtained by constructing properly the boundary layer. Finally, numerical results are given, which provide a strong support for the analytical estimates. 展开更多
关键词 spectral analysis multiscale asymptotic expansion second order ELLIPTIC operator rapidly OSCILLATinG coefficient perforated domain.
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