首页 | 本学科首页   官方微博 | 高级检索  
相似文献
 共查询到19条相似文献,搜索用时 992 毫秒
1.
A k-subset D of a group G of order v (1 < k < v -1 ) is called a (v, k, )-difference set ifevery nonidentity element of G appears in the list of d1d2-1(d1, d2 D) exactly times. Setn = k - , n is called the order of difference set D.An taomorphism of a finite group G is called a (right) multiplier of a difference set D inG if sends D onto Da for some a G. If G is abelian and if is given by g gt, where t isan integer prime to the order of G, then and also t itself are called a numerical mul…  相似文献   

2.
Block diagonal dominance of matrix and spectral inclusion regions   总被引:1,自引:0,他引:1  
Suppose that comlex matrix A or order n is partitioned as where the diagonal submatrices A_(ⅱ) are square of order n_i(1≤i≤N) .If each A_(ⅱ)is nonsingular and satisfies sum from (j=1 j≠i) to N(‖A_(ij)~(-1)A_(ij)‖≤1),1≤i≤N. thon A is called quasi-block diagonally domfnant. Specially, if strictly inequality in(2) is valid for all 1≤i≤N then A is called quasi-block strictly diagonally dominant. If strict inequality in (2) is valid for at least one i (1≤i≤N) and  相似文献   

3.
Let v be a positive integer and let K be a set of positive integers. A (v, K, 1)-Mendelsohn design, which we denote briefly by (v, K, 1)-MD, is a pair (X, B) where X is a v-set (of points) and B is a collection of cyclically ordered subsets of X (called blocks) with sizes in the set K such that every ordered pair of points of X are consecutive in exactly one block of B. If for all t =1, 2,..., r, every ordered pair of points of X are t-apart in exactly one block of B, then the (v, K, 1)-MD is called an r-fold perfect design and denoted briefly by an r-fold perfect (v, K, 1)-MD. If K = {k) and r = k - 1, then an r-fold perfect (v, (k), 1)-MD is essentially the more familiar (v, k, 1)-perfect Mendelsohn design, which is briefly denoted by (v, k, 1)-PMD. In this paper, we investigate the existence of 4-fold perfect (v, (5, 8}, 1)-Mendelsohn designs.  相似文献   

4.
Let B be a Banach space, Φ1 , Φ2 be two generalized convex Φ-functions and Ψ 1 , Ψ 2 the Young complementary functions of Φ1 , Φ2 respectively with ∫t t 0 ψ2 (s) s ds ≤ c 0 ψ1 (c 0 t) (t > t 0 ) for some constants c 0 > 0 and t 0 > 0, where ψ1 and ψ2 are the left-continuous derivative functions of Ψ 1 and Ψ 2 , respectively. We claim that: (i) If B is isomorphic to a p-uniformly smooth space (or q-uniformly convex space, respectively), then there exists a constant c > 0 such that for any B-valued martingale f = (f n ) n ≥ 0 , ‖f*‖Φ1 ≤ c‖S (p) (f ) ‖Φ2 (or ‖S (q) (f )‖Φ1 ≤ c‖f*‖Φ2 , respectively), where f and S (p) (f ) are the maximal function and the p-variation function of f respec- tively; (ii) If B is a UMD space, T v f is the martingale transform of f with respect to v = (v n ) n ≥ 0 (v*≤ 1), then ‖(T v f )*‖Φ1 ≤ c ‖f *‖Φ2 .  相似文献   

5.
An LRHTS(v)(or LARHTS(v)) is a collection of {(X, B i) : 1 ≤ i ≤ 4(v-2)},where X is a v-set, each(X, B i) is a resolvable(or almost resolvable) HTS(v), and all B i s form a partition of all cycle triples and transitive triples on X. An OLRHTS(v)(or OLARHTS(v))is a collection {(Y \{y}, A j y) : y ∈ Y, j = 0, 1, 2, 3}, where Y is a(v + 1)-set, each(Y \{y}, A j y)is a resolvable(or almost resolvable) HTS(v), and all A j y s form a partition of all cycle and transitive triples on Y. In this paper, we establish some directed and recursive constructions for LRHTS(v), LARHTS(v), OLRHTS(v), OLARHTS(v) and give some new results.  相似文献   

6.
Let simple graph G=(V, E),V=n,E=m. If there exists a path containing i vertices connecting u and v in V, then property P_i(u,v) will be said to told.For 2≤i≤n, let S_i be the set of all unordered pairs of distinct u and v for which property P_i(u.v) holds, and Let S_1 be the set of all unordered pairs of vertices which are not connected by any path. A graph G satisfies property P_i if |S_i|=n(n-1)/2.  相似文献   

7.
I. Cahit calls a graph H-cordial if it is possible to label the edges with the numbers from the set{1,-1} in such a way that, for some k, at each vertex v the sum of the labels on the edges incident with v is either k or-k and the inequalities |v(k)-v(-k)| ≤ 1 and|e(1)-e(-1)| ≤ 1 are also satisfied. A graph G is called to be semi-H-cordial, if there exists a labeling f, such that for each vertex v, |f(v)| ≤ 1, and the inequalities |e_f(1)-e_f(-1)| ≤ 1 and |vf(1)-vf(-1)| ≤ 1 are also satisfied. An odd-degree(even-degree) graph is a graph that all of the vertex is odd(even) vertex. Three conclusions were proved:(1) An H-cordial graph G is either odd-degree graph or even-degree graph;(2) If G is an odd-degree graph, then G is H-cordial if and only if |E(G)| is even;(3) A graph G is semi-H-cordial if and only if |E(G)| is even and G has no Euler component with odd edges.  相似文献   

8.
Let G(V, E) be a graph. A k-adjacent vertex-distinguishing equatable edge coloring of G, k-AVEEC for short, is a proper edge coloring f if (1) C(u)≠C(v) for uv ∈ E(G), where C(u) = {f(uv)|uv ∈ E}, and (2) for any i, j = 1, 2,… k, we have ||Ei| |Ej|| ≤ 1, where Ei = {e|e ∈ E(G) and f(e) = i}. χáve (G) = min{k| there exists a k-AVEEC of G} is called the adjacent vertex-distinguishing equitable edge chromatic number of G. In this paper, we obtain the χáve (G) of some special graphs and present a conjecture.  相似文献   

9.
This paper summarized recent achievements obtained by the authors about the box dimensions of the Besicovitch functions given byB(t) := ∞∑k=1 λs-2k sin(λkt),where 1 < s < 2, λk > 0 tends to infinity as k →∞ and λk satisfies λk 1/λk ≥λ> 1. The results show thatlimk→∞ log λk 1/log λk = 1is a necessary and sufficient condition for Graph(B(t)) to have same upper and lower box dimensions.For the fractional Riemann-Liouville differential operator Du and the fractional integral operator D-v,the results show that if λ is sufficiently large, then a necessary and sufficient condition for box dimension of Graph(D-v(B)),0 < v < s - 1, to be s - v and box dimension of Graph(Du(B)),0 < u < 2 - s, to be s uis also lim k→∞logλk 1/log λk = 1.  相似文献   

10.
A λ-fold triple system of order v,denoted TS(v,λ),is a pair(V,A)where V is a v-set and A is a collection of 3-subsets(called triples)of V such that each 2-subset of V is contained in exactly λ triples.A triple system is called simple if itcontains no repeated triples. There are two related classes of triple systems,namely,Mendelsohn triple sys-tems and directed triple systems.  相似文献   

11.
1. Introduction and Main ResultsSuppose the population of interest consists of N distinct units labelled by 1,' f N.Associated with unit i are two values K and Xi, with Xi > 0 (i = 1,' t N). Denote thepopulation means of K and X, by Y and X respectively. To estimate Y, it is customaryto select a simple raPdom sample of size n and to use the ratio estimatNn = RX if Xis available, where R = y/x is an estimator for population ratio R = Y/X, y and x arerespectively the 8ample mean8 of…  相似文献   

12.
设F_q是q个元素的有限域,q是2的幂,F_q~(2ν+δ+l)是F_q上2ν+δ+l维行向量空间,Ps_(2ν+δ+l,2ν+δ)(F_q)是F_q上级数为2ν+δ+l而秩为2ν+δ的伪辛群.F_q~(2ν+δ+l)在Ps_(2ν+δ+l,2ν+δ)(F_q)的作用下划分成一些子空间轨道Μ(m,2s+τ,s,∈,k;2ν+δ,2ν+δ).采用矩阵初等行变换的方法,给出轨道Μ(m,2s+τ,s,∈,k;2ν+δ,2ν+ε)的长度.  相似文献   

13.
A signed(res. signed total) Roman dominating function, SRDF(res.STRDF) for short, of a graph G =(V, E) is a function f : V → {-1, 1, 2} satisfying the conditions that(i)∑v∈N[v]f(v) ≥ 1(res.∑v∈N(v)f(v) ≥ 1) for any v ∈ V, where N [v] is the closed neighborhood and N(v) is the neighborhood of v, and(ii) every vertex v for which f(v) =-1 is adjacent to a vertex u for which f(u) = 2. The weight of a SRDF(res. STRDF) is the sum of its function values over all vertices.The signed(res. signed total) Roman domination number of G is the minimum weight among all signed(res. signed total) Roman dominating functions of G. In this paper,we compute the exact values of the signed(res. signed total) Roman domination numbers of complete bipartite graphs and wheels.  相似文献   

14.
1IntroductionInthispaper,Weuse[1]forterminologyandnotationnotdefinedhereandconsiderfinitesillWlegraphsonlyThedistancebetweenverticesuandvisdenotedbyd(u,v)-ForeachvertexuEV(G),wedeuotebyN(u)thesetofallverticesofGadjacenttou.ThesubgraphofGinducedbyN(u)U{u}isdenotedbyG(u).IfuveE(G),wedenotebyS(u,v)thenumberofedgesofmaximumstarincludingu5vasaninducedsubgraphinG.Letxai1dybetwoverticesinGwitl1d(x,y)=2,wedefineI(x,y)=IN(x)nN(y)I.LetCbeacycleofGwithafixedcyclicorientation.ForuEV(C),letu be…  相似文献   

15.
The concept of derivations and generalized inner derivations has been generalized as an additive function δ: R→ R satisfying δ(xy) = δ(x)y xd(y) for all x,y∈R,where d is a derivation on R.Such a function δis called a generalized derivation.Suppose that U is a Lie ideal of R such that u2 ∈ U for all u ∈U.In this paper,we prove that U(C)Z(R) when one of the following holds:(1)δ([u,v]) = uov (2)δ([u,v]) uov=O(3)δ(uov) =[u,v](4)δ(uov) [u,v]= O for all u,v ∈U.  相似文献   

16.
On the elements of the ring of residues modulo v (zτ v, 3τ v) we construct cyclic PBIB-designs with τ(v)-1 classes of connectedness, where τ(v) is the number of divisors of v. We prove the existence of cyclic BIB-designs with parameters b, v, r, k, and λ such that: 1) λ=k (and also λ=k/2 if k is even), k≥4, and (k-1) ¦ (p-1) for each prime divisor p of the number v; 2) λ=(k?l)/2, k odd, k≥3, k ¦ (p?1) for each prime divisor p of the number v.  相似文献   

17.
可迹图即为一个含有Hamilton路的图.令$N[v]=N(v)\cup\{v\}$, $J(u,v)=\{w\in N(u)\cap N(v):N(w)\subseteq N[u]\cup N[v]\}$.若图中任意距离为2的两点$u,v$满足$J(u,v)\neq \emptyset$,则称该图为半无爪图.令$\sigma_{k}(G)=\min\{\sum_{v\in S}d(v):S$为$G$中含有$k$个点的独立集\},其中$d(v)$表示图$G$中顶点$v$的度.本论文证明了若图$G$为一个阶数为$n$的连通半无爪图,且$\sigma_{3}(G)\geq {n-2}$,则图$G$为可迹图; 文中给出一个图例,说明上述结果中的界是下确界; 此外,我们证明了若图$G$为一个阶数为$n$的连通半无爪图,且$\sigma_{2}(G)\geq \frac{2({n-2})}{3}$,则该图为可迹图.  相似文献   

18.
徐利治  吳智泉 《数学学报》1955,5(2):161-172
<正> 在作者之一的文章[1]中,曾定義過一種含有参數的正規變換函數類。對於以這類中的函數為核所構成的積分變換,即存在有一種廣義的Stieltjes-Post-Widder反演公式。在本文的第一節中,我們將對正規變換函數定義中的第二條件予以减弱,也就是把核函數的範圍加以放寬,而仍保持廣義反演公式的有效.在本文的第二節中,主要是改善先前一篇短文[2]中的結果,我們將在較廣泛的條件下,重新建立某一漸近積分定理.  相似文献   

19.
对于图G(或有向图D)内的任意两点u和v,u—v测地线是指在u和v之间(或从u到v)的最短路.I(u,v)表示位于u—v测地线上所有点的集合,对于S(?)V(G)(或V(D)),I(S)表示所有I(u,v)的并,这里u,v∈S.G(或D)的测地数g(G)(或g(D))是使I(S)=V(G)(或I(S)=V(D))的点集S的最小基数.G的下测地数g~-(G)=min{g(D):D是G的定向图},G的上测地数g~ (G)=max{g(D):D是G的定向图}.对于u∈V(G)和v∈V(H),G_u H_v表示在u和v之间加一条边所得的图.本文主要研究图G_u H_v的测地数和上(下)测地数.  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