共查询到20条相似文献，搜索用时 93 毫秒
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设置={1,2,……,n},CT（Xn）={α ∈ Tn：Vx,y∈Xn,d（xα,yα）≤d（x,y）},本文在已有的文献的基础上,研究了半群CT（Xn）的幂等元性质. 相似文献
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设Xn={1,2,…,n},Q（Xn）={A1,A2,…,Ar}为Xn上任意一个划分,令OCT（Xn）={α∈On：Ai,Aj∈Xn,d（Aiα,Ajα）≤d（Ai,Aj）},则OCT（Xn）是一个半群。本文刻划了该半群的Green关系及一些相关的性质。 相似文献
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设Xn={1,2,…,n},Sn,In分别为Xn上的置换群与对称逆半群,令PDIn={α∈In\Sn:x,y∈dom α■︱xα-yα︱=︱x-y︱},那么PDIn为In的一个子半群,称为保距变换半群.本文给出了保距变换半群PDIn的基数. 相似文献
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设Xn={1,2,…,n}是有限全序集,Tn是有限集Xn上的全变换半群,易知它的子集TD(Xn)={α∈Tn:x∈Xn,x|n→ xα|n}是Tn上的一个子半群,称之为保整除变换半群,令DOn={α∈TD(Xn):x,y∈Xn,x≤y→xα≤yα},则DOn是TD(Xn)的一个子半群,称之为保整除保序有限变换半群,在此刻划了DOn的Green关系和正则元。 相似文献
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保距变换半群PDI_n的Green关系 总被引：1，自引：1，他引：0
设Xn={1,2,…,n},记Sn,In分别为Xn上的置换群与对称逆半群,令PDIn={α∈In／Sn：x,y∈domα■｜xα-yα｜=｜x-y｜},那么PDIn为In的一个子半群,称为保距变换半群.在这篇文章中主要刻画了半群PDIn的Green关系. 相似文献
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1．（陕西）已知全集U={1,2,3,4,5},集合A={x｜x^2-3x＋2=0},B={x｜x=2a,a∈A},则集合Cu（AUB）中元素的个数为（ ）． 相似文献
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第一试 一、选择题(每小题6分,共36分) 1.已知集合E={x|x=cos((nπ)/3),n∈z},F={x|x=sin(((2m-3)π)/6),m∈z}。则E与F的关系 相似文献
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一、选择题1.设集合U={1,2,3,4,5},A={1,2,3},B={2,5},则A∩(CUB)=()(A){2}(B){2,3}(C){3}(D){1,3}2.已知集合M={x｜x=3m+1,m∈Z},N={y｜y=3n+2,n∈Z},若x0∈M,y0∈N,则x0y0与集合M,N的关系是()(A)x0y0∈M但x0y0N(B)x0y0∈N但x0y0M(C)x0y0M且x0y0N(D)x0y0∈M且x0y0∈N3.已知集合A={-1,2},B={x｜mx+1=0},若A∪B=A,则实数m的取值所成的集合是()(A)-1,12(B)-12,1(C)-1,0,12(D)-12,0,14.设P={3,4,5},Q={4,5,6,7},定义PQ={(a,b)｜a∈P,b∈Q},则PQ中元素的个数为()(A)7(B)10(C)12(D)205.设集合P=x｜｜x+12｜<12,Q={m｜x2-4m… 相似文献
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设X为有限集合,E为X上的等价关系且Ix为x上的对称逆半群。令IE·（X）={f∈,Ix（x,y）∈E当且仅当（f（x）,f（y））∈E},则IE·（X）是Ix的逆子半群。设DIE·（X）为IE·（X）中所有E类保序或反保序变换构成的半群,讨论了它的Green关系。 相似文献
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邱崇丙 《唐山师范学院学报》2014,(1):21-23
汉字的六书,《说文》对“转注”一类,语焉不详。后世学者提及转注,也仅限于许慎所举出的例字。《汉字例说》一文,作者从转注的角度综合考虑,对部分现代常用字作了分析,跟传统的解释有所不同。希望能抛砖引玉,互相切磋,以推进学术研究。 相似文献
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《海外英语》2007,(5):10-11
Many college freshmen arrive woefully unprepared to do college work, and as disadvantaged populations continue to grow, the share of the American work force that has made it through college is expected to plummet. Many experts blame that educational failure not just on high schools but also on colleges. School & College, a special report by The Chronicle, looks at efforts to fix the system. What reforms would better prepare students for college? What should schools and colleges be doing differently? How should state and federal officials help? 相似文献
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Rachel Zupek 《海外英语》2007,(11):40-41
我们绝大部分人都同意一件事情——我们喜欢金钱。但是你对金钱的喜欢之情足够到让你创立一份事业么?.财富通常被人忽视,主要在于人们不能真正了 相似文献
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《海外英语》2007,(4):36
There are numbers of crossroads on our long and unpredictable life journey where we totally have no idea about which direction to choose. No matter what our decision is, we should not turn back, but face the music and go ahead instead. I am this kind of girl who always does try without regretting, one example is how I dealt with my love. 相似文献
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YANGShiguo 《重庆大学学报(英文版)》2004,3(1):86-88
The problem on the geometrc inequalities involving an n-dimensional simplex and its inscribed simplex is studied. Aninequality is established, which reveals that the difference between the squared circumradius of the n-dimensional simplex andthe squared distance between its circumcenter and barycenter times the squared circumradius of its inscribed simplex is not lessthan the 2(n-1)th power of n times its squared inradius, and is equal to when the simplex is regular and its inscribed siplex is atangent point one. Deduction from this inequality reaches a generalization of n-dimensional Euler inequality indicating that thecircumradius of the simplex is not less than the n-fold inradius. Another inequality is derived to present the relationship betweenthe circumradius of the n-dimensional simplex and the circumradius and inradius of its pedal simplex. 相似文献
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Migration occurs behind a variety of reasons and has a great effect on the whole world. People may migrate in order to improve their economic situation, or in order to escape civil strife, persecution, and environmental disasters. The impact of migration is complex, bringing both benefits anddisadvantages. This paper briefly talks about the causes of migration, the allocation of benefits, and the ways in which individual countries and the international community deal with this important subject. 相似文献
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GUO Bao-feng Xiao Da-wei 《重庆大学学报(英文版)》2005,4(3):129-133
Using virtual reality for interactive design gives a designer an intuitive vision of a design and allows the designer to achieve a viable, optimal solution in a timely manner. The article discusses the process of making the Virtual Reality System of the Humble Administrator＇s Garden. Translating building data to the Virtual Reality Modeling Language （VRML） is by far unsatisfactory. This creates a challenge for computer designers to do optimization to meet requirements. Five different approaches to optimize models have been presented in this paper. The other methods are to optimize VRML and to reduce the file size. This is done by keeping polygon counts to a minimum and by applying such techniques as object culling and level-ofdetail switching. 相似文献