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1.
关于图的符号控制数的下界   总被引:7,自引:0,他引:7  
图的符号控制数的研究有许多应用背景,但图的符号控制数的计算是NP完全问题,因而确定其上下界有重大意义。本文在[5]的基础上,引进了新参数δ^*(G),全面改进了[5]所给出的符号控制数的下界,并给出了一些可达下界的图。  相似文献   

2.
《Quaestiones Mathematicae》2013,36(4):371-381
ABSTRACT

The circulant graph Cp > a1,…, ak < with 0 > a1 >…> ak >(pt1)/2 has p vertices labeled 0,1,…,p-1 and x and y are adjacent if and only if x—y = ± ai (mod p) for some i. We prove the following regarding the chromatic index of a circulant: if d = gcd (a1,…, ak, p), then x' (Cp > al,…,ak) = Δ(C p > a1,…,ak) if and only if p/d is even.  相似文献   

3.
关于图的下完美邻域数的上界一些结果   总被引:1,自引:0,他引:1  
本文主要讨论了图的下完美邻域数 ,并给出了θ(G) =γ(G)的充分必要条件 ,并讨论了一些特殊图类的下完美邻域数的上界 ,特别对于树采用了对所有点分层的方法进行了较细致的讨论 ,给出了紧上界θ(T)≤ [n3] .  相似文献   

4.
树图边色数的界   总被引:1,自引:0,他引:1  
刘浩培 《数学杂志》2002,22(1):100-102
本文研究树图的边色数,确定了其上界与下界,并进而考虑界的精确性。  相似文献   

5.
《Quaestiones Mathematicae》2013,36(4):381-385
ABSTRACT

A connected, nontrivial, simple graph of order v is said to be α,β destructible if α,β are integral factors of v and an α-set of edges, E', exists whose removal from G isolates exactly the vertices in a β-set V'. Graphs which are not α, β destructible for any α.β are called stable. In this paper we prove that all graphs on a non-prime number v of vertices are α,β destructible for some a which divides v.  相似文献   

6.
7.
《Quaestiones Mathematicae》2013,36(2):175-178
ABSTRACT

A connected, nontrivial, simple graph of order v is said to be α,β destructible if α,β are factors of v and an α-set of edges, E', exists whose removal from G isolates exactly the vertices in α,β-set V'. Graphs which are not α,β destructible for any α,β are called stable, If G is a stable graph on a prime number p ≥ 7 of vertices, then we show that G has a maximum number of edges if and only if G is K2,p-2, We also characterize stable graphs on a minimum number of edges.  相似文献   

8.
研究半导体方程解的整体性质,应用Stampacchia的最大模估计方法,证明了解的上下界整体估计.  相似文献   

9.
控制γ和连通控制数γc是图的两个重要的控制参数,本文通过对树中的点进行恰当分类,给出了树中的γ/γc值的最好界,为刻画单圈图和双圈图中γ/γc值的界打下良好的基础。  相似文献   

10.
§ 1 IntroductionThe maximum genusγM(G) of a graph G is the maximum among the genera,which Ghas a cellularembedding on a sphere with k handles.Since any embedding of G has atleastone face,by Euler polyhedral equation,itcan be obtained thatγM(G)≤β(G) / 2 ,whereβ(G) is the Betti number of G.A graph G is called up-embeddable ifγM(G) =β(G) / 2 .[1 ] has showed that thereare atleasttwo edge-disjointspanning trees in G if G is 4 -edge connected.Let T be a span-ning tree of G.An odd …  相似文献   

11.
设α(G)表示简单图G=(V,E)的独立数.本文给出了α(G)的一个新的下界:α(G)≥∑v∈V(λd(v)+1)/(d(v)+λd(v)+1),其中λd(v)=max{0,βN(v)-d(v)},d(v)=|N(v)|,N(v)={w∈V|(v,w)∈E},βN(v)=minw∈N(v)d(w).  相似文献   

12.
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14.
《Quaestiones Mathematicae》2013,36(1-2):291-313
Abstract

A 0-dominating function 0DF of a graph G = (V,E) is a function f: V → [0,1] such that Σ xεN(v) f(x) ≥ 1 for each ν ε V with f(v) = 0. The aggregate of a 0DF f is defined by ag(f) = ΣvεV f(v) and the infimum and supremum of the set of aggregates over all minimal 0DFs of a graph are denoted by γ0 and Γ0 respectively. We prove some properties of minimal 0DFs and determine γ0 and Γ0 for some classes of graphs.  相似文献   

15.
戴勇  邓玲芳 《数学杂志》2013,33(1):153-156
本文研究了空间曲面的等周亏格问题.利用R3中卵形区域的高斯曲率K及著名的等周小等式,得到R3中卵形区域的等周亏格的几个上界估计.  相似文献   

16.
《Quaestiones Mathematicae》2013,36(1-2):275-289
Abstract

Numerical solution of the wave equation in the form of close lower and upper bounds provides a secure a posteriori error estimate that can be used for efficient accuracy control. The method considered in this paper uses some monotone properties of the differential operator in the wave equation to construct bounds for the solution in the form of trigonometric polynomials of x. Aspects of the numerical implementation, the accuracy of the computed bounds and some numerical examples are discussed.  相似文献   

17.
18.
1引言本文讨论非负矩阵Perron根的上界。设  相似文献   

19.
与最小度有关的图的最大亏格的下界   总被引:5,自引:0,他引:5  
设G为简单图且最小度不小于3.结合G边连通性,文中分别给出了与最小度有关的G的最大亏格的下界表达式。  相似文献   

20.
树的四类控制参数的束缚数   总被引:4,自引:0,他引:4  
吴亚平  范琼 《数学杂志》2004,24(3):267-270
图的束缚数是图的控制数研究中的一个重要方面,它在某种程度上反映了图的控制数对边数的敏感度.本文通过对图的结构特征的分析.研究了树的四类控制参数的束缚数,即控制数,强控制数,弱控制数.分数控制数的束缚数.分别给出了其紧的上界.  相似文献   

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