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1.
In this paper, we investigate flows on discrete curves in     , and     . A novel interpretation of the one-dimensional Toda lattice hierarchy and reductions thereof as flows on discrete curves are given.  相似文献   

2.
张中峰  袁平之 《数学学报》2010,53(1):199-204
本文证明了乘积 (f(x)=ax2+bx+c∈Z[x]是二次不可约多项式)在n充分大时不是平方数.    相似文献   

3.
 We estimate the error of asymptotic formulae for volume approximation of sufficiently differentiable convex bodies by circumscribed convex polytopes as the number of facets tends to infinity. Similar estimates hold for approximation with inscribed and general polytopes and for vertices instead of facets. Our result is then applied to estimate the minimum isoperimetric quotient of convex polytopes as the number of facets tends to infinity.  相似文献   

4.
李云章  周凤英 《数学学报》2010,53(3):551-562
本文讨论中约化子空间上的仿射(伪仿射)对偶小波标架.我们建立了仿射系与伪仿射系之间的一个标架 和对偶标架保持定理,并且在没有任何衰减性假设的条件下获得了仿射(伪仿射)对偶小波标架在傅立叶域上的一个刻画.进一步, 我们也给出了仿射Parseval标架在傅立叶域上的刻画.    相似文献   

5.
 We give a formula for the -discrepancy of the 2-dimensional Hammersley point set in base 2 for all integers p, .  相似文献   

6.
关于树T的b.gif (280 bytes)的界   总被引:1,自引:0,他引:1  
《数学杂志》2003,23(2):185-188
控制数γ和连通控制数γc是图的两个重要的控制参数.本文通过对树中的点进行恰当分类,给出了树中的γ/γc值的最好界,为刻画单圈图和双圈图中γ/γc值的界打下良好的基础.  相似文献   

7.
通过一个例子说明在[3]中定理2.2的证明中用到的一个结论是错误的,并给出该定理的一种正确证明。  相似文献   

8.
 In this paper we show that shifts of finite type satisfying a strong topological mixing property are universal models for ergodic measure preserving dynamical systems.  相似文献   

9.
 The complex two-plane Grassmannian carries a K?hler structure J and also a quaternionic K?hler structure ?. For we consider the classes of connected real hypersurfaces (M, g) with normal bundle such that and are invariant under the action of the shape operator. We prove that the corresponding unit Hopf vector fields on these hypersurfaces always define minimal immersions of (M, g), and harmonic maps from (M, g), into the unit tangent sphere bundle with Sasaki metric . The radial unit vector fields corresponding to the tubular hypersurfaces are also minimal and harmonic. Similar results hold for the dual space .  相似文献   

10.
设R和S是环,U是平坦右R-模,V是平坦右S-模.本中我们证明了(N,(U,V))-lc.dim(R S)=sup((N,U)-lc.dimR,(N,V)-lc.dimS).  相似文献   

11.
给出(S↑-)模糊积分的定义,讨论其基本性质。当模糊测度μ满足(T)条件(见命题3.3)时,可以得到,(S↑-)模糊积分的p次(S↑-)模糊可积函数空间Lp(p≥1)是实数域R上的线性空间,且当μ次可加时,Lp(p≥1)在相应的距离ρp(定义4.3)下,(Lp,ρp)构成一完备的距离空间。  相似文献   

12.
《数学研究与评论》2004,24(1):155-158
本文证明(1)如果X=∏σ∈∑Xσ是|Σ|-仿紧空间,则X是正规弱(-θ)-可加空间当且仅当 F∈[∑]<ω,∏σ∈FXσ是正规弱(-θ)-可加空间.(2)设X=∏i∈ωXi是可数仿紧的,则下列三条等价X是正规弱(-θ)-可加的; F∈[ω]<ω,∏i∈FXi是正规弱(-θ)-可加的; n∈ω,∏i≤nXi是正规弱(-θ)-可加的.  相似文献   

13.
14.
《数学研究与评论》2004,24(1):173-179
讨论了(~ρ)混合序列的强收敛性,获得了与独立情形几乎一致的结果,推广了著名的Marcinkiewicz-Zygmund强大数律.  相似文献   

15.
In this article.a normalized biholomorphic mapping f defined on bounded starlike circular domain in C″is considered,where z=0 is a zero of order k 1 of f(z)(?) The sharp growth.covering theorems for almost starlike mappings of order a and starlile mappings of order wave established.Meanwhile,the construction of the above mappings on bounded starlike circular domain in C~n is also discussed,it provides the extremal mappings for the growth,covering theorems of the above mappings.  相似文献   

16.
17.
In this paper we consider a generalized version of the classical preemptive open shop problem with sum of weighted job completion times objective. The main result is a (2+)-approximation algorithm for this problem. In the last section we also discuss the possibility of improving our algorithm.  相似文献   

18.
The main result of this paper is a (2 + )-approximation scheme for the minimum dominating set problem on circle graphs. We first present an O(n2) time 8-approximation algorithm for this problem and then extend it to an time (2 + )-approximation scheme for this problem. Here n and m are the number of vertices and the number of edges of the circle graph. We then present simple modifications to this algorithm that yield (3 + )-approximation schemes for the minimum connected and the minimum total dominating set problems on circle graphs. Keil (1993, Discrete Appl. Math.42, 51–63) shows that these problems are NP-complete for circle graphs and leaves open the problem of devising approximation algorithms for them. These are the first O(1)-approximation algorithms for domination problems on circle graphs.  相似文献   

19.
李英奎  马涛 《数学杂志》2005,25(2):119-122
讨论了Cn单位球上的向量值Dpμ,q函数, 利用Banach空间几何学的方法,推广了标量值Dpμ,q函数的结果.  相似文献   

20.
Let X be an arbitrary Banach space, K be a nonempty closed convex subset of X, and T : KK be a Lipschitzian and hemicontractive mapping with the property lim inft→∞((t)/t) > 0. It is shown that the Ishikawa iteration procedures are weakly T-stable. As consequences, several related results deal with the weak stability of these procedures for the iteration proximation of solutions of nonlinear equations involving accretive operators. Our results improve and extend those corresponding results announced by Osilike.  相似文献   

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