共查询到20条相似文献,搜索用时 62 毫秒
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数与式1.若a≠0,则下列运算正确的是( ).(A)a4·a2=a8 (B)a2+a2=a4(C)(-3a4)2=9a6(D)(-a)4÷(-a)2=a22.下列各式中计算错误的是( ).(A)ab=acbc(c≠0)(B)a+bab=a2+aba2b(C)0.5a+b0.2a-0.3b=5a+10b2a-3b(D)x-yx+y=y-xy+x3.化简12-3的结果是( ). (A)-2+3 (B)-2-3(C)2+3(D)2-34.2x2·3x3等于( ).(A)6x5 (B)6x6 (C… 相似文献
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设M是二维紧致、曲率K(M)≤0的Riemann流形.对任一x M,在M上类数≥3的点集非空且只有有限个点{α1,α2,…;αd}.用Kj表示αj的类数,即αj到x的最短测地线的条数.那么,M的Euler数X(M)可以表示为:X(M)=(d+1)=Kj.如果M上类数23的点只有一个,那么这个点是M上距离x最远的点. 相似文献
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关于任意K(K≥5)个连续Fibonacci数的猜想 总被引:7,自引:2,他引:5
关于任意K(K≥5)个连续Fibonacci数的猜想刘元宗(河南洛阳师专471022)文[1]指出,1991年美国Mr.A.DiDomenico教授利用数学归纳法证明了五个连续Fibonacci数的几个公式,即(1)FnFn+4-Fn+1Fn+3=2... 相似文献
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设d,a,k,n是适合4k^2n+1=da^2,k〉1,n〉2,d无平方因子的正整数;又设C(K)和h(K)分别是实二次域K=Q(√d)的理想类群和类数。本文证明了:当a〈0.5k^0.56n时,则h(K)≡0(mod n)和C(K)必有n阶循环子群。 相似文献
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一、填空(每题4分,共40分)1一元二次方程的一般形式是(其中)它的求根公式为(其中)2已知关于x的方程x2-px+2p=0的一个根为1,则p=,它的另一个根为3直接写出下列方程的解(1)2(x-1)(x+3)=0(2)3x2+4x-1=04三个连续奇数中,中间一个奇数用2k+1表示,则其余两个奇数为和5某厂今年用电5万度,为节约能源,计划每年要比上一年节约x%,预计明年用电万度,后年用电万度6一元二次方程3x2-5x-1=0的△=,此方程的根的情况是7在实数范围内分解… 相似文献
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设d,a,k,n是适合4k2n+1=da2,k>1,n>2,d无平方因子的正整数;又设C(K)和h(K)分别是实二次域K的理想类群和类数.本文证明了:当a<0.5k0.56n时,则h(k)=0(modn)和C(K)必有n阶循环子群. 相似文献
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二维带形无界区域中Navier—Stokes方程整体吸引子及其维数估计 总被引:5,自引:0,他引:5
该文讨论二维无界带形区域中Navier-Stokes方程(Ⅰ){ut-△u+uiэuэxi=-△p+f(x,t)∈Ω×R+(1)divu=0(2)u(X,t)∈(H^10(Ω)for t〉0(3)u(x,0)=u0(x)∈H(4)其中Ω=(0,d)×R,d〉0为一常数,u与p为未知量,其中u=(u1,u2)为速度场,p表示压力。我们证明了当u0∈H,f∈V且f「log(e+│x│^2)」^12∈L 相似文献
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关于连续Fibonacci数的公式简超(武汉铁路成人中专430012)设Fn表示Fibonacci数:F1=F2=1,Fn+2=Fn+Fn+1,n=1,2,3,…并约定F0=0.本文给出关于连续Fibonacci数的几类公式,并证明文[1]的猜想成立... 相似文献
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本文研究了一类整数序列(2n)2n 1的某些性质,利用费玛数和数论函数的某些性质,获得了验证此类整数是否是亲和数和完全数的方法,既不与其他正整数构成亲和数对也不是完全数. 相似文献
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V. Yegnanarayanan 《Southeast Asian Bulletin of Mathematics》2000,24(1):129-136
The pseudoachromatic number of a graph G is the maximum size of a vertex partition of G (where the sets of the partition may or may not be independent) such that, between any two distinct parts, there is at least one edge of G. This parameter is determined for graphs such as cycles, paths, wheels, certain complete multipartite graphs, and for other classes of graphs. Some open problems are raised.AMS Subject Classification (1991): primary 05C75 secondary 05C85 相似文献
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Kyriakos Keremedis 《Mathematical Logic Quarterly》1999,45(1):95-104
We find topological characterizations of the pseudointersection number ?? and the tower number t of the real line and we show that ?? < t iff there exists a compact separable T2 space X of π-weight < ?? that can be covered by < t nowhere dense sets iff there exists a weak Hausdorff gap of size K < t, i. e., a pair ({A : i ≠ k}, {BJ : j ε K}) C [W]W X [U]W such that A = {Ai : i ε K} is a decreasing tower, B = {Bj : j ε K) is a family of pseudointersections of A, and there is no pseudointersection S of A meeting each member of B in an infinite set. 相似文献
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Bohdan Zelinka 《Czechoslovak Mathematical Journal》2005,55(2):393-396
The restrained domination number r(G) and the total restrained domination number
t
r
(G) of a graph G were introduced recently by various authors as certain variants of the domination number (G) of (G). A well-known numerical invariant of a graph is the domatic number d(G) which is in a certain way related (and may be called dual) to (G). The paper tries to define analogous concepts also for the restrained domination and the total restrained domination and discusses the sense of such new definitions.This research was supported by Grant MSM 245100303 of the Ministry of Education, Youth and Sports of the Czech Republic. 相似文献
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Futaba Okamoto Ping Zhang Varaporn Saenpholphat 《Czechoslovak Mathematical Journal》2008,58(1):271-287
For a nontrivial connected graph G of order n and a linear ordering s: v
1, v
2, …, v
n
of vertices of G, define . The traceable number t(G) of a graph G is t(G) = min{d(s)} and the upper traceable number t
+(G) of G is t
+(G) = max{d(s)}, where the minimum and maximum are taken over all linear orderings s of vertices of G. We study upper traceable numbers of several classes of graphs and the relationship between the traceable number and upper
traceable number of a graph. All connected graphs G for which t
+(G) − t(G) = 1 are characterized and a formula for the upper traceable number of a tree is established.
Research supported by Srinakharinwirot University, the Thailand Research Fund and the Commission on Higher Education, Thailand
under the grant number MRG 5080075. 相似文献
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设n是大于1的正常数,并且设n=pα11p2α2…ptαt,其中pi为素数,i=1,2,…,t,ω(n)表示n的不同素因子的个数,即ω(n)=t.若n的所有因子的倒数和为整数,即0≤∑ij≤αjj=1,2,…,t1p1i1pi22…ptit为整数,称n是调和数.证明了和调和数相关的一个结论. 相似文献
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Jing-wen Li Zhi-wen Wang Jaeun Lee Moo Young Sohn Zhong-fu Zhang En-qiang Zhu 《应用数学学报(英文版)》2010,26(3):525-528
In this paper we get some relations between α(G), α'(G), β(G), β'(G) and αT(G), βT(G). And all bounds in these relations are best possible, where α(G), α'(G),/3(G), β(G), αT(G) and βT(G) are the covering number, edge-covering number, independent number, edge-independent number (or matching number), total covering number and total independent number, respectively. 相似文献
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Izolda Gorgol 《Graphs and Combinatorics》2008,24(4):327-331
A subgraph of an edge-colored graph is called rainbow if all of its edges have different colors. For a graph H and a positive integer n, the anti-Ramsey number f (n, H) is the maximum number of colors in an edge-coloring of K
n
with no rainbow copy of H. The rainbow number
rb(n, H) is the minimum number of colors such that any edge-coloring of K
n
with rb(n, H) number of colors contains a rainbow copy of H. Certainly rb(n, H) = f(n, H) + 1. Anti-Ramsey numbers were introduced by Erdős et al. [4] and studied in numerous papers.
We show that for n ≥ k + 1, where C
k
+ denotes a cycle C
k
with a pendant edge. 相似文献
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ANoteontheBondageNumberofaGraph¥LiYuqiang(DepartmentofMathematics,GuangzhouTeacher'sCollege)Abstract:Thebondagenumberb(G)ofag... 相似文献
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