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分形插值的条件 被引量:6
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作者 龙晶凡 《北京师范大学学报(自然科学版)》 CAS CSCD 北大核心 2001年第3期289-291,共3页
对于一类重要的迭代函数系统给出了G ={ (x ,f(x) ) :x∈I}为其惟一吸引子的充要条件 ,并利用此结论给出了重要等式∫IH(x ,f(x) )dx=∑Nn =1an∫IH(Ln(x) ,Fn(x ,f(x) )dx的一种简单证明方法 (其中 f(x)为迭代函数系统生成的分形插值函... 对于一类重要的迭代函数系统给出了G ={ (x ,f(x) ) :x∈I}为其惟一吸引子的充要条件 ,并利用此结论给出了重要等式∫IH(x ,f(x) )dx=∑Nn =1an∫IH(Ln(x) ,Fn(x ,f(x) )dx的一种简单证明方法 (其中 f(x)为迭代函数系统生成的分形插值函数 ,H(x ,f(x) )∈L(I) ,I =[x0 ,xN]) . 展开更多
关键词 迭代函数系统 吸引子 分形插值函数 垂直压缩因子 IFS 充要条件
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有限带函数在C(R)空间中用一样条的回复
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作者 龙晶凡 《北京师范大学学报(自然科学版)》 CAS CSCD 北大核心 1999年第3期310-315,共6页
证明了若-样条伴随的n阶微分算子只有实特征根,且这些特征根关于n—致有界,则有限带函数可以由—样条一致回复.
关键词 有限带函数 回复 R-样条 微分算子 样条函数
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TRACTABILITY OF MULTIVARIATE INTEGRATION PROBLEM FOR PERIODIC CONTINUOUS FUNCTIONS 被引量:1
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作者 房艮孙 龙晶凡 《Acta Mathematica Scientia》 SCIE CSCD 2007年第4期790-802,共13页
The authors study the tractability and strong tractability of a multivariate integration problem in the worst case setting for weighted 1-periodic continuous functions spaces of d coordinates with absolutely convergen... The authors study the tractability and strong tractability of a multivariate integration problem in the worst case setting for weighted 1-periodic continuous functions spaces of d coordinates with absolutely convergent Fourier series. The authors reduce the initial error by a factor ε for functions from the unit ball of the weighted periodic continuous functions spaces. Tractability is the minimal number of function samples required to solve the problem in polynomial in ε^-1 and d, and the strong tractability is the presence of only a polynomial dependence in ε^-1. This problem has been recently studied for quasi-Monte Carlo quadrature rules, quadrature rules with non-negative coefficients, and rules for which all quadrature weights are arbitrary for weighted Korobov spaces of smooth periodic functions of d variables. The authors show that the tractability and strong tractability of a multivariate integration problem in worst case setting hold for the weighted periodic continuous functions spaces with absolutely convergent Fourier series under the same assumptions as in Ref,[14] on the weights of the Korobov space for quasi-Monte Carlo rules and rules for which all quadrature weights are non-negative. The arguments are not constructive. 展开更多
关键词 Information-based complexity TRACTABILITY Monte Carlo methods multivariate integration
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Riesz基,Paley-Wiener类和缓增样条 被引量:1
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作者 房艮孙 龙晶凡 《中国科学(A辑)》 CSCD 1999年第8期680-687,共8页
设T ={tj}j∈Z为实序列 ,使得 {eitjξ}j∈Z构成L2 ( [-π ,π])的一个Riesz基 .设S2m(T ,R)∩L2 (R)是以T ={tj}j∈Z为非正规节点系的多项式缓增样条函数空间 .证明了S2m(T ,R)∩L2 (R)上的Marcinkiewicz Zygmund和Bernstein不等式 .... 设T ={tj}j∈Z为实序列 ,使得 {eitjξ}j∈Z构成L2 ( [-π ,π])的一个Riesz基 .设S2m(T ,R)∩L2 (R)是以T ={tj}j∈Z为非正规节点系的多项式缓增样条函数空间 .证明了S2m(T ,R)∩L2 (R)上的Marcinkiewicz Zygmund和Bernstein不等式 .并由此证得渐近关系 :E(f,Bπ ,2 ) 2 =limm→∞ E(f,S2m(T ,R) ∩L2 (R) ) 2 ,其中Bπ ,2 表示L2 (R)中指数≤π的整函数 ,即经典的Paley Wiener类 . 展开更多
关键词 RIESZ基 整函数 缓增样条 Paley-Wiener类
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Riesz basis, Paley-Wiener class and tempered splines 被引量:1
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作者 房艮孙 龙晶凡 《Science China Mathematics》 SCIE 2000年第10期1075-1082,共8页
The Marcinkiewicz-Zygmund inequality and the Bernstein inequality are established on which is the space of polynomial splines with irregularly distributed nodes T = where is a real sequence such that constitutes a Rie... The Marcinkiewicz-Zygmund inequality and the Bernstein inequality are established on which is the space of polynomial splines with irregularly distributed nodes T = where is a real sequence such that constitutes a Riesz basis for L2([ -π, π]) . From these results, the asymptotic relationis proved, where Bπ,2 denotes the set of all functions from L2(R) which can be continued to entire functions of exponential type ≤π, i.e. the classical Paley- Wiener class. 展开更多
关键词 RIESZ BASIS entire functions tempered splines ASYMPTOTIC relation.
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