The extension of the D(?k 2)-pair {k 2,k 2 + 1}

Let n be a nonzero integer. A set of m distinct positive integers is called a D(n)-m-tuple if the product of any two of them increased by n is a perfect square. Let k be a positive integer. In this paper, we show that if {k ², k ²+1, c, d} is a D(?k ²)-quadruple with c < d, then c = 1 and d = 4k ²+1. This extends the work of the first author [20] and that of Dujella [4].     

Schrijver图SG(2k+2,k)的Hamilton性

通过图G的每个顶点的路称为Hamilton路,通过图G的每个顶点的圈称为Hamilton圈,具有Hamilton圈的图G称为Hamilton图.1952年Dirac曾得到关于Hamilton图一个充分条件的结论:图G有n个顶点,如果每个顶点υ满足:d(υ)≥n/2,则图G是Hamilton图.本文研究了Schrijver图SG(2k+2,k)的Hamilton性,采用寻找Hamilton圈的方法得出了Schrijver图SG(2k+2,k)是Hamilton图.     

具有色多项式∑n＋2／k[k n＋2—k]（λ）k＋1的图

本文讨论了色项式为∑/k≤n 2(n 2)/k[k n 2-k](λ）k 1的图的结构,给出了具有这种色多项式的全部色等价图。     

On codimensions k immersions of m-manifolds for k = 1 and k = m − 2

Let us consider M a closed smooth connected m-manifold, N a smooth (2m − 2)-manifold and a continuous map, with . We prove that if is injective, then f is homotopic to an immersion. Also we give conditions to a map between manifolds of codimension one to be homotopic to an immersion. This work complements some results of Biasi et al. (Manu. Math. 104, 97–110, 2001; Koschorke in The singularity method and immersions of m-manifolds into manifolds of dimensions 2m − 2, 2m − 3 and 2m − 4. Lecture Notes in Mathematics, vol. 1350. Springer, Heidelberg, 1988; Li and Li in Math. Proc. Camb. Phil. Soc. 112, 281–285, 1992).     

具有常余维数2k+4不动点集的(Z2)k作用

本文通过构造上协边环MO*的一组生成元决定了J*,k2k 4.     

关于空间(k1,k2)-拟正则映射

本文考虑空间 (k1,k2 ) -拟正则映射的 Lp(p >n)可积性 ,以及当 k1→ 1 ,k2 → 0时 p的渐近行为 .     

退化（k1，k2）拟正则映射的充分条件

研究了退化弱（k1,k2）拟正则映射的正则性．利用Holder不等式、Sobolev空间的空间分析方法,以及内插定理等工具,给出了退化弱（k1,k2）拟正则映射事实上为退化（k1,k2）拟正则映射的一个充分条件,其结果对非退化情形也成立．     

关于空间（k1,k2）—拟正则映射

本文考虑空间（ｋ１,ｋ２）－拟正则映射的Ｌ＾ｐ（ｐ〉ｎ）可积性,以及当ｋ１→１,ｋ２→０时ｐ的渐近行为。     

敢于跳出思维的惯区——(-π/2+2kπ,π/2+2kπ)(k∈Z)能成为定义域吗?

1 一则引例 文[1]着重阐述了区间这一中学数学基础概念的理解,指出如(-∞,0)∪(0,+∞)并不是一个区间,而是一个开集.由此纠正了中学数学教师对函数的单调区间不能作并集根本原因的认识.     

均衡二部图中含2k条指定边的k个独立圈及2-因子

得到了对于二部图G=(V_1,V_2;E),当|V_1|=|V_2|=n≥2k+1时的结果:对G中任意2k条独立边e_1,e_1~*,…,e_k,e_k~*,G中一定存在k个独立的4-圈C_1,C_2,…,C_k,使得对任意i∈{1,2,…,k}有{e_i,e_i~*}E(C_i).并在此基础上进一步证明了当|V_1|=|V_2|=n≥3k时若对任意两顶点x∈V_1,y∈V_2,都有d(x)+d(y)≥2n-k+1成立,则G有一个2-因子含有k+1个独立圈C_1,C_2,…,C_(k+1)使得对任意i∈{1,2,…,k}有{e_i,e_i~*}E(C_i)且|C_i|=4.     

Linking (n − 2)-dimensional panels inn-space I: (k − 1,k)-graphs and (k − 1,k)-frames

A (k – 1,k)-graph is a multi-graph satisfyinge (k – 1)v – k for every non-empty subset ofe edges onv vertices, with equality whene = |E(G)|. A (k – 1,k)-frame is a structure generalizing an (n – 2, 2)-framework inn-space, a structure consisting of a set of (n – 2)-dimensional bodies inn-space and a set of rigid bars each joining a pair of bodies using ball joints. We prove that a graph is the graph of a minimally rigid (with respect to edges) (k – 1,k)-frame if and only if it is a (k – 1,k)-graph. Rigidity here means infinitesimal rigidity or equivalently statical rigidity.     

关于Sk=1+2k+3k+…+nk的探究

1.递推公式由二项展开式得对i求和上式左边可化为(n+1)k+1-1+Sk+1,从而有(1)由(1)式得递推公式     

具有小k的线本原2—（v,k,1）设计

ＡｎｎｅＤｅｌｎｄｔｓｈｅｅｒ在［１］中证明了：如果Ｇ在２－（ｖ，ｋ，１）设计上线本原，且ｋ＜３０，则Ｇ点本原，本文将ｋ范围扩大到了ｋ≤４０。     

Z2k上的二次剩余码

Hammons利用Gray映射把一些具有良好纠错能力的非线性码与Z4上的线性码建立了联系.本文进-步对更-般的环上的循环码进行研究,我们定义了Z2k上-类特殊的循环码-二次剩余码,证明了它的存在性及个数,并且证明了它与域上的二次剩余码有类似的性质.     

Isodual Codes over ℤ2k and Isodual Lattices

A code is called isodual if it is equivalent to its dual code, and a lattice is called isodual if it is isometric to its dual lattice. In this note, we investigate isodual codes over _2k . These codes give rise to isodual lattices; in particular, we construct a 22-dimensional isodual lattice with minimum norm 3 and kissing number 2464.