共查询到20条相似文献,搜索用时 78 毫秒
1.
该文讨论了线性流形上矩阵方程AX=B反对称正交对称反问题的最小二乘解及其最佳逼近问题. 给出了最小二乘问题解集合的表达式, 得到了给定矩阵的最佳逼近问题的解, 最后给出计算任意矩阵的最佳逼近解的数值方法及算例. 相似文献
2.
对于Ricci曲率下有界的紧连通Riemann流形,其Laplace算子的第一特征值的线性逼近如何? 这里给出了使用计算机辅助证明的解答,它在一定意义下是最佳的. 相似文献
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本文讨论了线性流形上用双反对称矩阵构造给定矩阵的最佳逼近问题,给出问题解的表达式,最后给出求最佳逼近解的数值方法与数值算例. 相似文献
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李珍珠 《数学的实践与认识》2011,41(11)
研究线性流形上广义次对称矩阵的左右逆特征值问题及其最佳逼近问题.利用广义次对称矩阵的性质及矩阵的奇异值分解得到问题的通解表达式.同时,给出其有唯一的最佳逼近解以及求最佳逼近解的算法. 相似文献
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该文讨论了线性流形上矩阵方程AX=B反对称正交对称反问题的最小二乘解及其最佳逼近问题.给出了最小二乘问题解集合的表达式,得到了给定矩阵的最佳逼近问题的解,最后给出计算任意矩阵的最佳逼近解的数值方法及算例. 相似文献
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给出了二次Hermite-Pad啨逼近的对偶性.证明了三次Hermite-Pad啨逼近的局部唯一性,并对其逼近阶进行估计. 相似文献
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本文通过构造形式级数的方式,给出了一种三维保测度映射系统中一维不变流形和二维不变流形的计算方法。利用不变流形的解析表达式我们估计了导致共振带完全失稳的临界参数。 相似文献
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Couette-Taylor流的谱Galerkin逼近 总被引:2,自引:0,他引:2
利用谱方法对轴对称的旋转圆柱间的Couette-Taulor流进行数值模拟.首先给出Navier-Stokes方程流函数形式,利用Couette流把边界条件齐次化.其次给出Stokes算子的特征函数的解析表达式,证明其正交性,并对特征值进行估计.最后利用Stokes算子的特征函数作为逼近子空间的基函数,给出谱Galerkin逼近方程的表达式.证明了Navier-Stokes方程非奇异解的谱Galerkin逼近的存在性、唯一性和收敛性,给出了解谱Galerkin逼近的误差估计,并展示了数值计算结果. 相似文献
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Linus Kramer 《Geometriae Dedicata》2000,79(3):321-339
In this third part, we consider those compact quadrangles which arise from isoparametric hypersurfaces of Clifford type and their focal manifolds. Sections 9–11 give a comprehensive introduction to these quadrangles from the incidence-geometric point of view. Section 10 contains also a new (algebraic) proof that these geometries are quadrangles.We determine which of these quadrangles have ovoids or spreads and also whether the normal sphere bundles of the focal manifolds admit sections, or whether they are topologically trivial. We give explicit geometric constructions for spreads, ovoids, and sections. 相似文献
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We study manifolds where the natural skew-symmetric curvature operator has pointwise constant eigenvalues. We give a local classification (up to isometry) of such manifolds in dimension 4. In dimension 3, we describe such manifolds up to a classification of three - dimensional Riemannian manifolds with principal Ricci curvatures r1 = r2 = 0, r3- arbitrary. We give examples of such manifolds in all dimensions which do not have constant sectional curvature; these manifolds are not pointwise Osserman manifolds in general. 相似文献
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LIN ShaoBo CAO FeiLong & XU ZongBen Institute for Information System Sciences Xi'an Jiaotong University Xi'an China 《中国科学 数学(英文版)》2011,(9)
In this paper,we investigate the radial function manifolds generated by a linear combination of radial functions.Let Wpr(Bd) be the usual Sobolev class of functions on the unit ball B d.We study the deviation from the radial function manifolds to Wpr(Bd).Our results show that the upper and lower bounds of approximation by a linear combination of radial functions are asymptotically identical.We also find that the radial function manifolds and ridge function manifolds generated by a linear combination of ridg... 相似文献
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We show that on some open sets, more general than balls, Runge approximation is possible in certain Banach spaces, and also in certain complex Banach manifolds. We also show that there is an entire holomorphic curve in Hilbert space on which there is a bounded holomorphic function on the trace of a ball that has no bounded holomorphic extension to even a smaller concentric ball. Using the same technique we also prove that a form of Runge approximation better than an error function is not always possible. 相似文献
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Victor Beresnevich 《Acta Mathematica Hungarica》2002,94(1-2):99-130
We deal with Diophantine approximation on the so-called non-degenerate manifolds and prove an analogue of the Khintchine–Groshev theorem. The problem we consider was first posed by A. Baker [1] for the rational normal curve. The non-degenerate manifolds form a large class including any connected analytic manifold which is not contained in a hyperplane. We also present a new approach which develops the ideas of Sprindzuk"s classical method of essential and inessential domains first used by him to solve Mahler"s problem [28]. 相似文献
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Bayram Ṣahin 《Central European Journal of Mathematics》2010,8(3):437-447
We introduce anti-invariant Riemannian submersions from almost Hermitian manifolds onto Riemannian manifolds. We give an example,
investigate the geometry of foliations which are arisen from the definition of a Riemannian submersion and check the harmonicity
of such submersions. We also find necessary and sufficient conditions for a Langrangian Riemannian submersion, a special anti-invariant
Riemannian submersion, to be totally geodesic. Moreover, we obtain decomposition theorems for the total manifold of such submersions. 相似文献
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We give necessary and sufficient conditions for totally real sets in Stein manifolds to admit Carleman approximation of class
Ck{\mathcal C^k}, k ≥ 1, by entire functions. 相似文献
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Debraj Chakrabarti 《Journal of Geometric Analysis》2008,18(3):720-739
We give examples of non-smooth sets in the complex plane with the property that every holomorphic map continuous to the boundary
from these sets into any complex manifold may be uniformly approximated by maps holomorphic in some neighborhood of the set
(Mergelyan-type approximation for manifold-valued maps.) Similar results are proved for sections of complex-valued holomorphic
submersions from complex manifolds.
相似文献
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We recall a curvature identity for 4-dimensional compact Riemannian manifolds as derived from the generalized Gauss–Bonnet formula. We extend this curvature identity to non-compact 4-dimensional Riemannian manifolds. We also give some applications of this curvature identity. 相似文献
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J. Ross 《Inventiones Mathematicae》2006,165(1):153-162
We give examples of smooth manifolds with negative first Chern class which are slope unstable with respect to certain polarisations, and so have Kähler classes that do not admit any constant scalar curvature Kähler metrics. These manifolds also have unstable Hilbert and Chow points. We compare this to the work of Song-Weinkove on the J-flow. 相似文献