首页 | 本学科首页   官方微博 | 高级检索  
相似文献
 共查询到20条相似文献,搜索用时 140 毫秒
1.
Abstract. How to verify that a given fuzzy set A∈F(X ) is a fuzzy code? In this paper, an al-gorithm of test has been introduced and studied with the example of test. The measure notionfor a fuzzy code and a precise formulation of fuzzy codes and words have been discussed.  相似文献   

2.
We give the structures of a cyclic code over ring
R = F2 + uF2 + u^2F2 = {0, 1,u, u^2,v, v^2,uv, v^3},
where u^3 = 0, of odd length and its dual code. For the cyclic code, necessary and sufficient conditions for the existence of self-dual code are provided.  相似文献   

3.
Let M be a compact Riemannian manifold of dimension m, N a complete Amply connected δ-pinched Riemannian manifold of dimension n. There exists a constant d(n). It is proved that if m≤d(n), then every minimizing map from M into N is smooth in the interior of M. If m=d(n)+1, such a map has at most diserete singular set and in general the Hausdorff dimension of the singular set is at most m-d(n)-1.  相似文献   

4.
Empirical likelihood inference for parametric and nonparametric parts in functional coefficient ARCH-M models is investigated in this paper. Firstly, the kernel smoothing technique is used to estimate coefficient function δ(x). In this way we obtain an estimated function with parameter β.Secondly, the empirical likelihood method is developed to estimate the parameter β. An estimated empirical log-likelohood ratio is proved to be asymptotically standard chi-squred, and the maximum empirical likelihood estimation(MELE) for β is shown to be asymptotically normal. Finally, based on the MELE of β, the empirical likelihood approach is again applied to reestimate the nonparametric part δ(x). The empirical log-likelohood ratio for δ(x) is proved to be also asymptotically standard chi-squred. Simulation study shows that the proposed method works better than the normal approximation method in terms of average areas of confidence regions for β, and the empirical likelihood confidence belt for δ(x) performs well.  相似文献   

5.
马忠泰 《数学季刊》1995,10(1):87-92
The real analyticity of δ-closed(p,q)-form Koppelman-Leray operator Tp,q is considered in this paper,and as a generation ,of [1],the integral solution operators of the δ-equation on an open set D with piecewise C^1-boundary locally preserve the real analyticity of δ-closed(p,q)-forms at boundary point near which δ D is totally convex in the complex tangential directions have been obtained.  相似文献   

6.
A subgroup of index p~k of a finite p-group G is called a k-maximal subgroup of G.Denote by d(G) the number of elements in a minimal generator-system of G and by δ_k(G) the number of k-maximal subgroups which do not contain the Frattini subgroup of G.In this paper,the authors classify the finite p-groups with δ_(d(G))(G) ≤ p~2 and δ_(d(G)-1)(G) = 0,respectively.  相似文献   

7.
Let f(x) be the density of a design variable X and m(x) = E[Y\X = x] the regression function. Then m(x) - G(x)/f(x), where G(x) = m(x)f(x). The Dirac δ-function is used to define a generalized empirical function Gn (x) for G(x) whose expectation equals G(x). This generalized empirical function exists only in the space of Schwartz distributions, so we introduce a local polynomial of order p approximation to Gn(.) which provides estimators of the function G(x) and its derivatives. The density f(x) can be estimated in a similar manner. The resulting local generalized empirical estimator (LGE) of m(x) is exactly the Nadaraya-Watson estimator at interior points when p = 1, but on the boundary the estimator automatically corrects the boundary effect. Asymptotic normality of the estimator is established. Asymptotic expressions for the mean squared errors are obtained and used in bandwidth selection. Boundary behavior of the estimators is investigated in details. We use Monte Carlo simulations to show that the  相似文献   

8.
A group of necessary and sufficient conditions for the nonoscillation of a second order linear delayequation with impulses(r(t)u')'=-p(t)u(t-τ)are obtained in this paper,where p(t)=sum from ∞to n=1 a_n δ(t-t_n),δ(t) is a Dirac δ-unction,and for each n∈N,a_n>0,t_n→∞as n→∞.Furthermore,the boundedness of the solutions is also investigated if the equationis nonoscillatory.An example is given to illustrate the use of the main theorems.  相似文献   

9.
For arbitrary c00, if A is a subset of the primes less than x with cardinality δx(logx)-1, δ≥(logx)-c0, then there exists a positive constant c such that the cardinality of A+A is larger than cδx(loglogx)-1.  相似文献   

10.
In this work, we obtain good upper bounds for the diameter of any graph in terms of its minimum degree and its order, improving a classical theorem due to Erd¨os, Pach, Pollack and Tuza.We use these bounds in order to study hyperbolic graphs(in the Gromov sense). To compute the hyperbolicity constant is an almost intractable problem, thus it is natural to try to bound it in terms of some parameters of the graph. Let H(n, δ_0) be the set of graphs G with n vertices and minimum degree δ_0, and J(n, Δ) be the set of graphs G with n vertices and maximum degree Δ. We study the four following extremal problems on graphs: a(n, δ_0) = min{δ(G) | G ∈ H(n, δ_0)}, b(n, δ_0) = max{δ(G) |G ∈ H(n, δ_0)}, α(n, Δ) = min{δ(G) | G ∈ J(n, Δ)} and β(n, Δ) = max{δ(G) | G ∈ J(n, Δ)}. In particular, we obtain bounds for b(n, δ_0) and we compute the precise value of a(n, δ_0), α(n, Δ) andβ(n, Δ) for all values of n, δ_0 and Δ, respectively.  相似文献   

11.
Let G be a graph with n(G) vertices and m(G) be its matching number.The nullity of G,denoted by η(G),is the multiplicity of the eigenvalue zero of adjacency matrix of G.It is well known that if G is a tree,then η(G) = n(G)-2m(G).Guo et al.[Jiming GUO,Weigen YAN,Yeongnan YEH.On the nullity and the matching number of unicyclic graphs.Linear Alg.Appl.,2009,431:1293 1301]proved that if G is a unicyclic graph,then η(G)equals n(G)-2m(G)-1,n(G)-2m(G),or n(G)-2m(G) +2.In this paper,we prove that if G is a bicyclic graph,then η(G) equals n(G)-2m(G),n(G)-2m(G)±1,n(G)-2m(G)±2or n(G)-2m(G) + 4.We also give a characterization of these six types of bicyclic graphs corresponding to each nullity.  相似文献   

12.
用P(G,λ)表示图G的色多项式.若对任意图H,当P(H,λ)=P(G,λ)时都有H和G同构,则称图G是色唯一的.给出了以下结果:m≥2且k≥0时,完全三部图K(m,m,m+k)是色唯一的;m≥2且m+1>k≥0时,完全三部图K(m,m+1,m+k)是色唯一的.  相似文献   

13.
几类图的匹配唯一性   总被引:19,自引:0,他引:19  
李改扬 《应用数学》1992,5(3):53-59
若图G的匹配多项式为M(G;W),对任何图H,M(G;W)=M(H;W)推出G与H同构,则称G是匹配唯一的.本文讨论了下面的几种图类:(i)B_(m,n,r);(ii)D_(m,n,r);(iii)T_(m,n)的匹配唯一性问题,从而得到一些较为满意的结果.  相似文献   

14.
设n,m和r是满足r≥2,n≥0,m≥3的整数,且当r是奇数时,假设r≥m-1.称一个图为K1,m-free,如果它不包含以Kt,m为导出的子图.称一个图G为一个(r,n)-临界图,如果在删去G的任意n个点后,剩下G的子图都有一个r-因子,设G是一个Kl,m-free的(n+1)-连通图,且阶为|G|以及r(|G|≥n)是偶数,证明了:如果G的最小度至少是r+n+m-1,阶|G|≥8r5+n,并且对V(G)的任意独立点集{x1,x2}都有|NG(x1)∪NG(x2)|≥(|G|+n)/2,那么G是一个(r,n)-临界图.关于G的最小度和|NG(x1)∪NG(X2)|的下界是紧的。  相似文献   

15.
图的无符号拉普拉斯矩阵是图的邻接矩阵和度对角矩阵的和,其特征值记为q1≥q2≥…≥qn.设C(n,m)是由n个顶点m条边的连通图构成的集合,这里1≤n-1≤m≤(n2).如果对于任意的G∈C(n,m)都有q1(G*)≥q1(G)成立,图G*∈C(n,m)叫做最大图.这篇文章证明了对任意给定的正整数a=m-n+1,如果n...  相似文献   

16.
Let I with |I| = k be a matching of a graph G (briefly, I is called a k-matching). If I is not a proper subset of any other matching of G, then I is a maximal k-matching and m(gk, G) is used to denote the number of maximal k-matchings of G. Let gk be a k-matching of G, if there exists a subset {e1, e2,…, ei} of E(G) \ gk, i (?)1, such that (1) for any j ∈ {1, 2,…,i}, gk + {ej} is a (k + l)-matching of G; (2) for any f ∈ E(G) \ (gk ∪ {e1,e2,…,ei}), gk + {f} is not a matching of G; then gk, is called an i wings k-matching of G and mi(gk,G) is used to denote the number of i wings k-matchings of G. In this paper, it is proved that both mi(gk,G) and m(gk,G) are edge reconstructible for every connected graph G, and as a corollary, it is shown that the matching polynomial is edge reconstructible.  相似文献   

17.
连通图G的一个k-树是指图G的一个最大度至多是k的生成树.对于连通图G来说,其毁裂度定义为r(G)=max{ω(G-X)-|X|-m(G-X)|X■V(G),ω(G-X)1}其中ω(G-X)和m(G-X)分别表示G-X中的分支数目和最大分支的阶数.本文结合毁裂度给出连通图G包含一个k-树的充分条件;利用图的结构性质和毁裂度的关系逐步刻画并给出图G包含一个k-树的毁裂度条件.  相似文献   

18.
李国君  刘桂真 《数学学报》2003,46(4):715-728
设G是一个图,具有顶点集合V(G)和边集合E(G).设g和f是定义在V(G)上的整数值函数,使对每个x∈V(G),有g(x)≤f(x).图G的一个(g,f)-因子是G的一个支撑子图H,使对每个x∈V(G),有g(x)≤d_H(x)≤f(x).G的一个(g,f)-因子分解是E(G)的边不相交的(g,g)-因子的一个划分.设F={F-1,F_2,…,F_m}为G的一个因子分解,H是G的一个有mr条边的子图.如果每个F_i恰好与H有r条公共边,1≤i≤m,则称Fr-正交于H.本文证明每个(mg+kr,mf-kr)-图含有一个子图R,使R有(g,f)-因子分解r-正交于任意给定的有kr条边的子图,其中m,k和r为正整数且k相似文献   

19.
Algebra and Logic - Let m be a positive integer and let Ω be a finite set. The m-closure of G ≤ Sym(Ω) is the largest permutation group G(m) on Ω having the same orbits as G in...  相似文献   

20.
2-(v,6,1)设计的可解区传递自同构群   总被引:13,自引:0,他引:13  
设G是一个2-(v,6,1)设计的可解区传递自同构群,且G非旗传递,则:(1)v=91,G=Z91×Zd,这里3|d|12;(2)v=pm,G≤AL(1,pm),之一成立.其中p≠2.当p=3时,4|m见且m>4;当p>5时,pm≡1(mod30)。  相似文献   

设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号