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对A.Hajnal和I.Juhasz问题的讨论
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作者 王延庚 《纯粹数学与应用数学》 CSCD 1990年第2期21-25,共5页
用部分子空间的基数函数值来估计整体空间的基数函数值,这是一个有趣的问题。M.G.Tkacenko曾经证明了下面定理: 定理1(见[1]):设X是非T_3空间,如果X满足条件:对任意Z?X,|Z|≤k(k>ω),有W(Z)<k,则W(X)<k。
关键词 Hajnal问题 Juhasz问题 拓扑空间 基数函数值
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Spherical Scattered Data Quasi-interpolation by Gaussian Radial Basis Function 被引量:2
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作者 Zhixiang CHEN Feilong CAO 《Chinese Annals of Mathematics,Series B》 SCIE CSCD 2015年第3期401-412,共12页
Since the spherical Gaussian radial function is strictly positive definite, the authors use the linear combinations of translations of the Gaussian kernel to interpolate the scattered data on spheres in this article. ... Since the spherical Gaussian radial function is strictly positive definite, the authors use the linear combinations of translations of the Gaussian kernel to interpolate the scattered data on spheres in this article. Seeing that target functions axe usually outside the native spaces, and that one has to solve a large scaled system of linear equations to obtain combinatorial coefficients of interpolant functions, the authors first probe into some problems about interpolation with Gaussian radial functions. Then they construct quasi- interpolation operators by Gaussian radial function, and get the degrees of approximation. Moreover, they show the error relations between quasi-interpolation and interpolation when they have the same basis functions. Finally, the authors discuss the construction and approximation of the quasi-interpolant with a local support function. 展开更多
关键词 Scattered data APPROXIMATION Spherical Gaussian radial basis function Modulus of continuity
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Prescribing Curvature Problems on the Bakry-Emery Ricci Tensor of a Compact Manifold with Boundary
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作者 Weimin SHENG Lixia YUAN 《Chinese Annals of Mathematics,Series B》 SCIE CSCD 2014年第1期139-160,共22页
t The authors consider the problem of conformally deforming a metric such that the k-curvature defined by an elementary symmetric function of the eigenvalues of the Bakry-Emery Ricci tensor on a compact manifold with ... t The authors consider the problem of conformally deforming a metric such that the k-curvature defined by an elementary symmetric function of the eigenvalues of the Bakry-Emery Ricci tensor on a compact manifold with boundary to a prescribed function. A consequence of our main result is that there exists a complete metric such that the Monge-Amp^re type equation with respect to its Bakry-Emery Ricci tensor is solvable, provided that the initial Bakry-Emery Ricci tensor belongs to a negative convex cone. 展开更多
关键词 k-Curvature Bakry-Emery Ricci tensor Complete metric Dirichletproblem
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