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1.
关于不含3正则子图图的最大边数   总被引:1,自引:1,他引:0  
对无自环、无重边的简单图,Erdos和Saucer在1974年提出如下问题:设 f(p) 是p个顶点的不含3正则子图图的最大可能边数,确定f(p).本文对p ≥4、4≤p≤40给出了f(p)的下界,对4p刁≤16给出了f(p)的值,并对4≤p ≤15得出了所有的极图.  相似文献   

2.
李宁 《科技信息》2009,(12):67-68
针对不同构的简单无向图的数目计算问题,本文在研究了置换群以及伯恩斯坦定理的基础上,以4个顶点的无向图为例,给出了具体的计算方法。  相似文献   

3.
无向同构图指的是在两个图中寻找顶点之间的映射关系,通过映射使原本形式各异的两图中的各条边保持对应的关系.为了有效提高寻找无向同构图的时间效率、简化操作,首先研究了无向图同构的矩阵存储方式,并针对性地提出了把无向图转换为有向图的同构算法.与矩阵存储算法相比,该判定算法的时间更为简短.最后给出了实现该算法的相关程序以及用该算法对无向图进行判定的过程和结果.  相似文献   

4.
规范标记算法和顶点划分算法是判断无向图同构的两种重要途径,其缺点是要么无法对图进行规范标记,从而不能进行判断;要么必须进行不断地回溯和试探,从而造成指数阶时间开销.对于任何两个同构的无向图,各自新增一个顶点和若干条关联边,可获得父图.当且仅当新增顶点的邻接点在原同构图中保持同构关系时,父图同构.根据这个充要条件,文中使...  相似文献   

5.
文章在电路模拟法的基础上提出了一种对称无向图的同构判定算法。电路模拟法对随机图的同构判定问题非常有效,但是对于处理对称度较高的图,判定效率明显降低甚至失效。该文提出的算法针对对称无向图的特性,在电路模拟法的基础上结合Dijkstra算法,综合得到顶点属性和最短距离序列来搜索顶点之间的映射关系,能够有效判定这类图的同构问题。  相似文献   

6.
首先研究得到了双变量色多项式的一般性的减边公式.接着对根图顶点进行了期望值研究,得出其减边公式,并由此得到一些特殊根图的期望值计算公式.最后讨论了正则q-树根图和正则q-树整子根图的期望值计算公式.  相似文献   

7.
传统的混合图的能量通过对方阵形式的矩阵特征值的计算而得到,难以推广应用到大规模的混合图中.针对这个问题,本文将网络维数应用于混合图中,提出了混合图的网络能量,从而将网络能量从无向图及有向图推广应用到混合图.混合图的网络能量可以通过混合图的节点数目及有向边与无向边的数目而得到,同时给出了混合图的网络能量的若干上下限.在与混合图的Hermitian能量及有向图与无向图的网络能量的对比中分析了所提出的混合图的网络能量的若干重要性质,并论证了无向图、有向图及混合图的网络能量三者之间的内在关联.  相似文献   

8.
一个简单无向图如果它正则且边传递但非点传递,则称为半对称图.该文给出了由有限群构造半对称图的一种新方法,并由此得到了一类半对称图的无限族的例子.  相似文献   

9.
1974年,Erdos和Saucer提出如下问题:设f(p)是p个顶点的不含3正则子图的图的最大可能边数,确定f(p)。本文给出:(1)f(p)≥3p-9,p≥4;(2)f(p)≥3p-5,p≥34。  相似文献   

10.
刻划了无环无向图的超边连通性(边连通性)与顶点最小度的关系。得到了边连通性、超边连通性的充分条件,并构造了非超边连通的图,由此表明定理1和定理2条件中的界是不能被改进的。  相似文献   

11.
Language markedness is a common phenomenon in languages, and is reflected from hearing, vision and sense, i.e. the variation in the three aspects such as phonology, morphology and semantics. This paper focuses on the interpretation of markedness in language use following the three perspectives, i.e. pragmatic interpretation, psychological interpretation and cognitive interpretation, with an aim to define the function of markedness.  相似文献   

12.
The discovery of the prolific Ordovician Red River reservoirs in 1995 in southeastern Saskatchewan was the catalyst for extensive exploration activity which resulted in the discovery of more than 15 new Red River pools. The best yields of Red River production to date have been from dolomite reservoirs. Understanding the processes of dolomitization is, therefore, crucial for the prediction of the connectivity, spatial distribution and heterogeneity of dolomite reservoirs.The Red River reservoirs in the Midale area consist of 3~4 thin dolomitized zones, with a total thickness of about 20 m, which occur at the top of the Yeoman Formation. Two types of replacement dolomite were recognized in the Red River reservoir: dolomitized burrow infills and dolomitized host matrix. The spatial distribution of dolomite suggests that burrowing organisms played an important role in facilitating the fluid flow in the backfilled sediments. This resulted in penecontemporaneous dolomitization of burrow infills by normal seawater. The dolomite in the host matrix is interpreted as having occurred at shallow burial by evaporitic seawater during precipitation of Lake Almar anhydrite that immediately overlies the Yeoman Formation. However, the low δ18O values of dolomited burrow infills (-5.9‰~ -7.8‰, PDB) and matrix dolomites (-6.6‰~ -8.1‰, avg. -7.4‰ PDB) compared to the estimated values for the late Ordovician marine dolomite could be attributed to modification and alteration of dolomite at higher temperatures during deeper burial, which could also be responsible for its 87Sr/86Sr ratios (0.7084~0.7088) that are higher than suggested for the late Ordovician seawaters (0.7078~0.7080). The trace amounts of saddle dolomite cement in the Red River carbonates are probably related to "cannibalization" of earlier replacement dolomite during the chemical compaction.  相似文献   

13.
何延凌 《科技信息》2008,(4):258-258
Language is a means of verbal communication. People use language to communicate with each other. In the society, no two speakers are exactly alike in the way of speaking. Some differences are due to age, gender, statue and personality. Above all, gender is one of the obvious reasons. The writer of this paper tries to describe the features of women's language from these perspectives: pronunciation, intonation, diction, subjects, grammar and discourse. From the discussion of the features of women's language, more attention should be paid to language use in social context. What's more, the linguistic phenomena in a speaking community can be understood more thoroughly.  相似文献   

14.
AcomputergeneratorforrandomlylayeredstructuresYUJia shun1,2,HEZhen hua2(1.TheInstituteofGeologicalandNuclearSciences,NewZealand;2.StateKeyLaboratoryofOilandGasReservoirGeologyandExploitation,ChengduUniversityofTechnology,China)Abstract:Analgorithmisintrod…  相似文献   

15.
理论推导与室内实验相结合,建立了低渗透非均质砂岩油藏启动压力梯度确定方法。首先借助油藏流场与电场相似的原理,推导了非均质砂岩油藏启动压力梯度计算公式。其次基于稳定流实验方法,建立了非均质砂岩油藏启动压力梯度测试方法。结果表明:低渗透非均质砂岩油藏的启动压力梯度确定遵循两个等效原则。平面非均质油藏的启动压力梯度等于各级渗透率段的启动压力梯度关于长度的加权平均;纵向非均质油藏的启动压力梯度等于各渗透率层的启动压力梯度关于渗透率与渗流面积乘积的加权平均。研究成果可用于有效指导低渗透非均质砂岩油藏的合理井距确定,促进该类油藏的高效开发。  相似文献   

16.
As an American modern novelist who were famous in the literary world, Hemingway was not a person who always followed the trend but a sharp observer. At the same time, he was a tragedy maestro, he paid great attention on existence, fate and end-result. The dramatis personae's tragedy of his works was an extreme limit by all means tragedy on the meaning of fearless challenge that failed. The beauty of tragedy was not produced on the destruction of life, but now this kind of value was in the impact activity. They performed for the reader about the tragedy on challenging for the limit and the death.  相似文献   

17.
本文叙述了对海南岛及其毗邻大陆边缘白垩纪到第四纪地层岩石进行古地磁研究的全部工作过程。通过分析岩石中剩余磁矢量的磁偏角及磁倾角的变化,提出海南岛白垩纪以来经历的构造演化模式如下:早期伴随顺时针旋转而向南迁移,后期伴随逆时针转动并向北运移。联系该地区及邻区的地质、地球物理资料,对海南岛上述的构造地体运动提出以下认识:北部湾内早期有一拉张作用,主要是该作用使湾内地壳显著伸长减薄,形成北部湾盆地。从而导致了海南岛的早期构造运动,而海南岛后期的构造运动则主要是受南海海底扩张的影响。海南地体运动规律的阐明对于了解北部湾油气盆地的形成演化有重要的理论和实际意义。  相似文献   

18.
There are numerous geometric objects stored in the spatial databases. An importance function in a spatial database is that users can browse the geometric objects as a map efficiently. Thus the spatial database should display the geometric objects users concern about swiftly onto the display window. This process includes two operations:retrieve data from database and then draw them onto screen. Accordingly, to improve the efficiency, we should try to reduce time of both retrieving object and displaying them. The former can be achieved with the aid of spatial index such as R-tree, the latter require to simplify the objects. Simplification means that objects are shown with sufficient but not with unnecessary detail which depend on the scale of browse. So the major problem is how to retrieve data at different detail level efficiently. This paper introduces the implementation of a multi-scale index in the spatial database SISP (Spatial Information Shared Platform) which is generalized from R-tree. The difference between the generalization and the R-tree lies on two facets: One is that every node and geometric object in the generalization is assigned with a importance value which denote the importance of them, and every vertex in the objects are assigned with a importance value,too. The importance value can be use to decide which data should be retrieve from disk in a query. The other difference is that geometric objects in the generalization are divided into one or more sub-blocks, and vertexes are total ordered by their importance value. With the help of the generalized R-tree, one can easily retrieve data at different detail levels.Some experiments are performed on real-life data to evaluate the performance of solutions that separately use normal spatial index and multi-scale spatial index. The results show that the solution using multi-scale index in SISP is satisfying.  相似文献   

19.
20.
The elongation method,originally proposed by Imamura was further developed for many years in our group.As a method towards O(N)with high efficiency and high accuracy for any dimensional systems.This treatment designed for one-dimensional(ID)polymers is now available for three-dimensional(3D)systems,but geometry optimization is now possible only for 1D-systems.As an approach toward post-Hartree-Fock,it was also extended to  相似文献   

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