A note of Romam dominating function

A Romam dominating function on a graph G = (V , E) is a function f : V → {0,1,2} satisfying the condition that every vertex v for which f(v)=0 is adjacent to at least one vertex x for which f(x)=2, denoted by f = (V0 , V1 , V2). The weight of a Roman dominating function is the value f(V)=∑v∈V=2n2 n1, where |Vi|= ni (i=0,1,2), the minimum weight of a Ronam dominating function denoted by γ R (G ). In this paper, we give an upper bound of γ R (G ), and at the same time, we answer an open problem posed in [1].     

图的符号全划分数

Let G = （V, E） be a graph, and let f ： V →{-1, 1} be a two-valued function. If ∑x∈N（v） f（x） ≥ 1 for each v ∈ V, where N（v） is the open neighborhood of v, then f is a signed total dominating function on G. A set {fl, f2,… fd} of signed d total dominating functions on G with the property that ∑i=1^d fi（x） ≤ 1 for each x ∈ V, is called a signed total dominating family （of functions） on G. The maximum number of functions in a signed total dominating family on G is the signed total domatic number on G, denoted by dt^s（G）. The properties of the signed total domatic number dt^s（G） are studied in this paper. In particular, we give the sharp bounds of the signed total domatic number of regular graphs, complete bipartite graphs and complete graphs.     

团图为数的图中的闭团贯数

Given a graph G,a subgraph C is called a clique of G if C is a complete subgraph of G maximal under inclusion and |C|≥2. A clique-transversal set S of G is a set of vertices of G such that S meets all cliques of G. The clique-transversal number, denoted as TC (G), is the minimum cardinality of a clique-transversal set in G. The clique-graph of G, denoted as K (G), is the graph obtained by taking the cliques of G as vertices, and two vertices are adjacent if and only if the corresponding cliques in G have nonempty intersection. Let F be a class of graphs G such that F={G|K(G) is a tree}. In this paper the graphs in F having independent clique-transversal sets are shown and thus TC (G)/|G|≤1/2 for all G ∈ F.     

求解有约束最优化问题的不连续罚函数积分总极值法

1IntroductionLetXbe a topological space ,Sa nonempty subsetofXandf:X→Ra real-valued function.Consider thefollowing constrained opti mization problem:c*=infx∈Sf(x) , (1)and the set of global mini mizers :H*={x∈S|f(x) =c*} (2)under the assumptions (see Refs .[1] and [2]) :(A) :fis lower semi-continuous ,Sis closed andthere is a real numberbsuch that the setHb={x∈S|f(x)≤b} is a nonempty compact set ;(R) :fis upper robust onS,i.e.,{x∈S|f(x) 相似文献   

One-parameter quasi-filled function algorithm for nonlinear integer programming

INTRODUCTION We consider the following nonlinear integerprogramming problem (PI) minf(x), s.t. x∈XI (1)where XI?In is a bounded and closed box set con-taining more than one point; In is the set of integerpoints in Rn. Notice that the formulation in (PI) allows the setXI to be defined by equality constraints as well asinequality constraints. Furthermore, when f(x) is co-ercive, i.e., f(x) → ∞ as ||x||→∞, there always exists abo…     

Longest Paths and Cycles in Connected Claw-Free Graphs

A graph is called claw-free if it does not contain a claw as its induced subgraph. In this paper, we prove the following results : 1 ) If G is a 2-connected claw-free graph on n vertices, then for any vertex υ and any two distinct vertices x and y in V(G) - |υ| , G has a path containing v and all neighbors of v and connecting x and y;2) Let C be the longest cycle in a 3-connected claw-free graph G and H a component of G - C,and if H is connected but not 2-connected, then there exist nonadjacent vertices u and v in H such that |V(C)| ≥3(d(u) d(u)) -2.     

障碍最优控制问题的正则性

1IntroductionIn this paper,we consider the following opti malcontrol problem.Problem(C)Find a-y∈H01(Ω),such thatI(-y)=infy∈H01(Ω)I(y),(1)whereI(y)21∫Ω{|T(y)-z|2 |y|2}dx,y∈H01(Ω),(2)andΩ∈Rnis a bounded domain with a boundaryΩ∈C1,andz∈L∞(Ω)is a giventarget profile.In ad-dition,φT(y)is the solution of thefollowing varia-tional inequality(also called state equation):φ∈K(y)={v∈H01(Ω)|v≥y,a.e.x∈Ω},∫Ωφ(v-φ)dx≥0,v∈K(y).(3)As is known,for everyy∈H01(Ω),(3)adm…     

直径为5的图的边直径稳定度

1　Introduction　Ingeneral,wefollowthenotationandterminologyof[1- 5 ].Inthispaperallgraphsaresimple .　LetGbeagraph ,V(G)thevertexsetofG ,andE(G)theedgesetofG .Thedistancebetweentwoverticesx ,y∈V(G) ,isdenotedbydG(x ,y) .ThediameterofGisdenotedbyd(G) .Apairofverticesx ,y∈V(G)suchthatdG(x ,y) =d(G)iscalledadiametricalpair.Forx ,y∈V(G) ,ashort (x ,y) pathisan (x ,y) pathwithlength≤d(G ) .ThelengthofapathPisdenotedby|P|.Anedgee∈E(G)iscalledcyclicifthereexistsacycleinGcontaining…     

Two-parameters quasi-filled function algorithm for nonlinear integer programming

INTRODUCTION Considering the following nonlinear integer programming problem: (PI) min f(x), s.t. x∈XI, (1) where XI?In is a bounded and closed box set con- taining more than one point, In is the set of integer points in n . If we suppose that f(x) satisfies the following conditions: if x∈XI, then f(x)=f(x), otherwise f(x)= ∞, then Problem PI is equal to the following nonlinear integer programming problem (UPI) min f(x), s.t. x∈In. (2) The formulation in PI allows the set XI t…     

Twin domination in generalized Kautz digraphs

Let G = （V,A） be a digraph.A set T of vertices of G is a twin dominating set of G if for every vertex v ∈ V ／ T.There exist u,w ∈ T （possibly u = w） such that （u,v）,（v,w） ∈ A.The twin domination number γ＊（G） of G is the cardinality of a minimum twin dominating set of G.In this paper we consider the twin domination number in generalized Kautz digraphs GK（n,d）.In these digraphs,we establish bounds on the twin domination number and give a sufficient condition for the twin domination number attaining the lower bound.We give the exact values of the twin domination numbers by constructing minimum twin dominating sets for some special generalized Kautz digraphs.     

循环群的一个新的特征性质(英文)

Two characteristic properties of a cyclic group are given: 1~0A group G is cyclic if and only every subgroup of G is G~mwhere G~m={X~n|X∈G}and m is a integer. See,[1] 2~0 A group G is cyclic if and only if the index of every subgroupof G is finite and for every positive integer k,in G at most thereexists a subgroup H having index k. See,[2]     

图的整数值控制函数

For an arbitrary subset P of the reals,a function f:V→P is defined to be a P-dominating function of a graph G=(V,E) if the sum of its function values over any closed neighbourhood is at least 1.That is,for every v∈V, f(N[v])≥1.The definition of total P-dominating function is obtained by simply changing‘closed’neighborhood N[v]in the definition of P-dominating function to‘open’neighborhood N(v).The (total) P-domination number of a graph G is defined to be the infimum of weight w(f) =∑_(v∈V)f(v) taken over all (total) P-dominating function f.Similarly,the P-edge and P-star dominating functions can be defined.In this paper we survey some recent progress oil the topic of dominating functions in graph theory.Especially,we are interested in P-,P-edge and P-star dominating functions of graphs with integer values.     

Calculation of Coefficients of Simplest Normal Forms of Hopf and Generalized Hopf Bifurcations

Consider the following dynamical system x.=f(x),x∈Rn(1)wherexis the state vector andfis analytic, assumingthatx=0 is an equilibrium of system (1), i.e.f(0) =0. Further, suppose that the Jacobian matrixevaluated on the equilibriumx=0 presents a purelyimag…     

2004年高考数学试题(全国卷):基本解法与巧思妙解(续二)

甘肃、宁夏、贵州、青海、新疆等地区使用试题　　一、选择题 :本大题共 1 2分 ,每小题 5分 ,共 60分 .( 1 )已知集合M ={0 ,1 ,2 },N ={x|x =2a ,a∈M},则集合M∩N =(　　 ) .A .{0 }　B .{0 ,1 }　C .{1 ,2 }　D .{0 ,2 }解 :∵N ={x|x =2a ,a∈M}={0 ,2 ,4},∴M∩N ={0 ,2 },故选D .( 2 ) 函数 y =e2x(x∈R)的反函数为 (　　 ) .A .y =2 1nx(x >0 )　　B .y =ln( 2x) (x >0 )C .y =12 lnx(x >0 )　D .y =12 ln( 2x) (x >0 )解法 1 :函数 y =e2x(x∈R)的值域为 y >0 ,反解得x =12 lny,故其反函数为 y=12 lnx(x >0 ) ,故选C .解法…     

大偶数表为两个素数之和（下）

In the paper: the representation of large even integer as a sum of two primes is proved to be right independently by each of W-progression ∑∞n=1(1)/((n+1)(n-1)!)of the discovery and the prime theorem. It is induced as two following problems which are solved for getting results of ration: Is there a function of f(2n) to be only dependent upon 2n or not? And it can express a number of group of prime solutions on representation of even integer as a sum of two primes. In one－dimensional space, the prime theorem is led into odd sequence integer to find P(G)～(2 )/(log n).P(G) is regarded as a data handling tool for setting a mathematical model of random sampling, get: P2n(1，1)n＞22n-P2=P1=f(2n)～(2nlogn/2)/(log2nlog2n)(2n→∞). The prime theorem π(x) is generalized to the two-dimensional space: π(x,y). A mathematical model of average values is set up by π(x,y), get: P2n(1，1)2n＞22n=P1+P2=f(2n)2～(2n)/(log22n)(2n→∞). But for expressing a number of group of prime solutions of even integer，the laws of values of principal steps of the two different functions f(2n) and f(2n)2 are unanimous. Thus, the proof of different ways lead to the same result and determines a forceful declaration: Goldbach’s conjecture is proved to be a right theorem.     

群的Fuzzy同态性质

研究群的Fuzzy同态性质，获得了子群W的像ψ2′(W)也是子群，不变子群H的像ψ2′(H)也是不变子群；构造了两个特殊不变子群L△↑={y∈G2|任意x∈G1,ψ(x，y)=ψ(x,e2)}。ψ2′(e2)△↑={x∈G1|ψ(x，e2)=1)} ,获得不变子群的一个重要性质及Fuzzy同态基本定理．     

Generalized Derivations in Prime Rings

Let R be a ring, a ,b ∈ R, ( D , α ) and (G , β ) be two generalized derivations of R . It is proved that if aD ( x ) = G ( x )b for all x ∈ R, then one of the following possibilities holds: (i) If either a or b is contained in C , then α = β= 0 and there exist p , q ∈ Qr ( RC) such that D ( x )= px and G ( x )= qx for all x ∈ R;(ii) If both a and b are contained in C , then either a = b= 0 or D and G are C-linearly dependent;(iii) If neither a nor b is contained in C , then there exist p , q ∈ Qr ( RC) and w ∈ Qr ( R) such that α ( x ) = [ q ,x] and β ( x ) = [ x ,p] for all x ∈ R, whence D ( x )= wx-xq and G ( x )= xp + avx with v ∈ C and aw-pb= 0.     

有向线图中的(k,l)-核

1 Introduction We consider the finite digraphs that do not havemultiple arcs or loops , but pairs of opposite arcs areallowed.LetD=(V,A) be a digraph , whereVisthe set of vertices andAis the set of arcs .If there isan arc (x,y) fromxtoy,thenthe vertexxis …     

关于图的全符号控制数

设G=(V,E)是一个非空图,对于一个函数f:V(G)∪E(G)→{-1,1},则称f的权重为w(f)=∑x∈V(G)∪E(G)f(x)。若x∈V(G)∪E(G),定义f[x]=∑y∈NT[x]f(y)。如果对所有的x∈V(G)∪E(G)都有f[x]≥1,则称f是图G的一个全符号控制函数。G的全符号控制数定义为γ*s(G)=min{w(f)|f是图G的一个全符号控制函数}。该文给出到了图的全符号控制数的一个上界,并研究了完全二部图Km,n的全符号控制数。     

带有边界阻尼的黏性波动方程的弱解

文章主要讨论下面具有边界阻尼的非线性黏性波动方程弱解的存在性及唯一性.设Ω是Rn的有界星形区域,其光滑边界为Γ=Γ0 UΓ1且Γ0与Γ1是不相交闭集,v为单位外法向量.在Ω上研究带有边界阻尼的非线性黏性波动方程yu-△y+∫01h(t-τ)△y(τ)dr+F(x,t,y,△y)=0,(V)(x,t)∈Ω×(0,∞);y=0,(V)(x,t)∈Γ1×(0,∞);(e)y/(e)v-(f)01∫01 h(t-τ)(e)y/(e)v(τ)dτ +byt=0,(V)(x,t)∈Γ0× (0,∞);y(x,0)=y0(x),yt(x,0)=y1(x),(V)x∈Ω其中b＞0.应用稠密性论证,把强解的存在性推广到弱解,并证明解的唯一性.