排序方式: 共有28条查询结果,搜索用时 0 毫秒
1.
The set D of distinct signed degrees of the vertices in a signed graph G is called its signed degree set. In this paper, we prove that every non-empty set of positive (negative) integers is the
signed degree set of some connected signed graph and determine the smallest possible order for such a signed graph. We also
prove that every non-empty set of integers is the signed degree set of some connected signed graph. 相似文献
2.
3.
S. Pirzada Merajuddin T. A. Naikoo 《分析论及其应用》2007,23(4):363-374
Let D(U, V, W) be an oriented 3-partite graph with |U|=p, |V|=q and |W|= r. For any vertex x in D(U, V, W), let d x and d-x be the outdegree and indegree of x respectively. Define aui (or simply ai) = q r d ui - d-ui, bvj(or simply bj) = p r d vj - d-vj and Cwk (or simply ck) = p q d wk - d-wk as the scores of ui in U, vj in V and wk in Wrespectively. The set A of distinct scores of the vertices of D(U, V, W) is called its score set. In this paper, we prove that if a1 is a non-negative integer, ai(2≤i≤n - 1) are even positive integers and an is any positive integer, then for n≥3, there exists an oriented 3-partite graph with the score set A = {a1,2∑i=1 ai,…,n∑i=1 ai}, except when A = {0,2,3}. Some more results for score sets in oriented 3-partite graphs are obtained. 相似文献
4.
Graeme Butt N. Pirzada Ronald D. Topsom William Adcock Anil N. Abeywickrema 《Tetrahedron letters》1982,23(21):2161-2162
The carbon-13 substituent chemical shifts of 4-substituted bicyclo[2.2.2]oct-1-yl cyanides are a linear function of the substituent inductive parameters. 相似文献
6.
Acta Mathematica Sinica, English Series - For a finite group G, the power graph $$\cal{P}(G)$$ is a simple connected graph whose vertex set is the set of elements of G and two distinct vertices x... 相似文献
7.
A loopless graph on n vertices in which vertices are connected at least by a and at most by b edges is called a(a,b,n)-graph. A(b,b,n)-graph is called(b,n)-graph and is denoted by K_n~b(it is a complete graph), its complement by K_n~b. A non increasing sequence π =(d_1,…,d_n) of nonnegative integers is said to be(a,b,n) graphic if it is realizable by an(a,b,n)-graph. We say a simple graphic sequence π=(d_1,…,d_n) is potentially K_4-K_2∪K_2-graphic if it has a a realization containing an K_4-K_2∪K_2 as a subgraph where K_4 is a complete graph on four vertices and K_2∪K_2 is a set of independent edges. In this paper, we find the smallest degree sum such that every n-term graphical sequence contains K_4-K_2∪K_2 as subgraph. 相似文献
8.
9.
M. Saleem Tahira Pirzada Riaz Qadeer 《Colloids and surfaces. A, Physicochemical and engineering aspects》2005,260(1-3):183-188
Sorption of some azo-dyes (acid violet 17, acid blue 90, acid red 1 and direct red 80) on locally available wool fiber from aqueous solution has been investigated as a function of shaking time, pH and dyes concentration as a function of temperature. Sorption isotherms for dyes on wool fiber were obtained. It was found that the increasing temperature induces positive effect on the sorption process. Isosteric heat of adsorption (qst) have also been calculated at different surface coverage indicating that wool fiber used possessed heterogeneous surface with site of different activity. The results also indicate that initial sorption whether chemical or physical means, occurs first on the most active sites and then, as the concentration of dyes is increased, on sites of lesser activity. 相似文献
10.
The set S of distinct scores (outdegrees) of the vertices of ak-partite tournamentT(X 1, X2, ···, Xk) is called its score set. In this paper, we prove that every set of n non-negative integers, except {0} and {0, 1}, is a score set of some 3-partite tournament. We also prove that every set ofn non-negative integers is a score set of somek-partite tournament for everyn ≥k ≥ 2. 相似文献