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1.
构造一条无切二次曲线用以研究一般的Ⅲ类方程x=-y+δx+lx2+mxy+ny2,y=x(1+ax+by)(n>0)的极限环之唯一性,得到了两个新的判别法.它们分别是对奇点O0,1n和O(0,0)外围的极限环给出的.  相似文献   

2.
关于迭代函数方程f~2(x)=af(x) bx的通解   总被引:2,自引:0,他引:2  
设λ的二次三项式λ2-aλ-b的两个零点为λ1=r,λ2=s(a及b为实数).对0<r<s,r<0<s≠-r及r=s≠0这三种情形,J.Matkowski与WeinianZhang在“Methodofcharacteristicsforfunctionalequationsinpolynomialform”一文中给出了迭代函数方程f2(x)=af(x)+bx,对任x∈R;f∈C0(R,R)(1)的通解,并证明了当r及s非实数时方程(1)无解.对r=-s≠0的情形,M.Kuczma已给出了方程(1)的通解.本文则对r<s<0及rs=0这两种情形给出了方程(1)的通解.此外,本文还给出了r<0<s≠-r时关于方程(1)的通解的一个简洁的证明  相似文献   

3.
U1-sr条件     
本文讨论U1-sr条件,这一条件有益于计算环的K1群.得到主要结果为;(1)完全确定满足U1-sr条件的半局部环:(2)给出使EndR(M)满足U1-sr条件的一个刻划;(3)引进比U1-sr更强的一个条件SU1-sr,利用上述结果证明了:若R∈SU1-sr,则Mn(R)∈U1-sr;(4)证明了对于满足SU1-sr的环R,K1R=GL1(R)ab.  相似文献   

4.
一类平面微分系统极限环的存在性与唯一性   总被引:1,自引:0,他引:1  
本文研究了平面微分系统x=-y+δx+mxy+ay2+by3,y=F(x)的极限环的存在唯一性,比较完整地讨论了参数空间,在全平面得到了无环和环存在的参数区域,发展了文[1]提出的比较对称轨线的方法,证明了只含一个奇点的极限环的唯一性,同时指出了含三个奇点的闭轨线族和奇闻轨线的存在性.  相似文献   

5.
费尔马最后定理的证明   总被引:2,自引:0,他引:2  
(i)我们用(x-b)n+xn=(x+a)来代替xn+yn=zn作为费尔马最后定理(FLT)的普遍方程式.其中a及b是两个任意自然数.应用二项展开式,(0.1)可以写成因为ar-(-b)r始终包含a+b作为它的因数,(0.2)可写成其中фr=[ar-(-b)r]/(a+b)对于r=1,2,…,n.都是个整数.(ii)令s是a+b的一个因数,并令a+b=sc.我们可用x=sy来变换(0.3)成为下列(0.4)(iii)将(0.4)除以S2,我们得(0.5)式的左边,是的整系数多项式,而右边cф/s是个常数Cф/s.若Cф/s不是个整数,那末我们不能求得能适合(0.5)的整数y,这样FLT对这场合是对问.若Cфn/s是个整数,我们可以改变s和c,使cф/s≠整数。  相似文献   

6.
本文考虑了椭圆曲线Γ_D:X ̄3+Y ̄3=DZ ̄3.以LD(s)记Γ_D的HeckeL-级数.由L_D(s)的解析延拓我们将L_D(1)展成有限项之和,然后通过建立y ̄2=x ̄3-16的一个处处有好的约化的模型,证明了当p≡2或5(mod 9)时,L_(p ̄2)(1)≠0.这些结果是对Birch和Swinnerfon-Dyer猜想的支持。  相似文献   

7.
圆的切线方程432100湖北孝感楚环中学徐圣明《平面解析几何》中有结论:经过圆x2+y2=2’上一点M(x0,y0)的切线方程是x0x+y0y=r2.由此命题,我们联想到它的两个道命题:Ⅰ若点P(x1,y1)在圆x2+y2=r2上,则直线x1x+y1...  相似文献   

8.
具有二个焦点的二次系统极限环的分布与个数   总被引:6,自引:0,他引:6  
张平光 《数学学报》2001,44(1):37-44
本文证明了具有二个焦点的二次系统必在其中一个焦点外围至多有一个极限环这一猜想.从而得到具有二个焦点的二次系统之极限环必是(O,i)或(1,i)分布(i= 0, 1, 2,).  相似文献   

9.
巫世权 《数学进展》1998,27(1):59-68
设n,s1,s2,…,sn为正整数及M(s1,s2,…,sn)={(x1,x2,…,xn)|0xisi,且xi为正整数}.若FM(s1,s2,…,sn)满足:对任何a,b∈F,都至少有t个i使ai∧bi=min(ai,bi)>0,则称F为M(s1,s2,…,sn)中的一个t-相交序列族.对x=(x1,x2,…,xn)∈M(s1,s2,…,sn),称r(x)=∑ni=1xi为x的秩.本文讨论并得到当s1=s2=…=sn时M(s1,s2,…,sn)中秩为k的有限序列最大相交族,从而获得了由Engel和Frankl提出的一个关于有限序列相交族的公开未解问题在kn+t-1情形下的解.  相似文献   

10.
{X,Xi,i≥1}是i.i.d.r.v′.s.在矩母函数存在的条件下,由古典的Erdos-Rényi大数律有limn→∞max0≤k≤n∑k+[clogn]i=k+1Xi[clogn]=α(c),α(c)为某常数.自正则下MiklósCsorgo&ShaoQiman(1994)在仅要求一阶矩的条件下就得到了:limn→∞max0≤k≤n∑k+[clogn]i=k+1Xi∑k+[clogn]i=k+1(X2i+1)=β(c),β(c)为某常数.众所周知,自正则下人们往往在较弱条件下取得相应结果是因为:分母中的X能有效抵销分子中X较大而引起整个分式极限行为的波动.因此,在什么样的条件下,式max0≤k≤n∑k+[clogn]i=k+1Xi∑k+[clogn]i=k+1X2i1-β[clogn]β→r(c)成为非常有意思的问题,因为它将依赖于β的大小.本文给出,当0<β≤12时,只要E(X)≥0,上式就有有限极限.当12<β<1时,则必须在矩母函数存在下,上式才有有限极限.并都求出了其极限表达式.  相似文献   

11.
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13.
An estimate of stability of characterization of distribution types is obtained for the case of additive types. Under some conditions, the estimate has the order ε1/3L(ε), where L(ε) is a slowly varying function. Proceedings of the Seminar on Stability Problems for Stochastic Models, Moscow, Russia, 1996, Part I.  相似文献   

14.
The asymptotic distribution of tensors of degree N in symmetry types is studied in this paper.Translated from Zapiski Nauchnykh Seminarov Leningradskogo Otdeleniya Matematicheskogo Instituta im. V. A. Steklova AN SSSR, Vol. 155, pp. 181–186, 1986.  相似文献   

15.
杨海宣 《数学学报》1998,41(4):727-730
本文研究了完全正则半群簇的子簇格[V+∩PV,V+∩PV]的某些格运算性质,我们证明了簇V+∩PV可分解为V与V+∩PV的并;对任意完全正则半群簇W,有W∩(V∨V+∩PV)=(W∩V)∨(W∩V+∩PV).特别地,我们得到了等式V+∩PV=V成立的若干条件.  相似文献   

16.
Yushkov  E. V. 《Mathematical Notes》2011,90(3-4):597-610
Mathematical Notes - We study the initial boundary-value problem for three-dimensional systems of equations of pseudoparabolic type. The system is similar to the Oskolkov system, but differs from...  相似文献   

17.
We give a characterization of the types of asymptotic discernibility of families of hypotheses in the case of hypothetical measures that are not, in general, mutually absolutely continuous. The case when the logarithm of the likelihood ratio admits an asymptotic expansion of the type of an expansion with local asymptotic normality is examined in detail. Examples are studied.Translated fromTeoriya Sluchainykh Protsessov, Vol. 15, pp. 64–71, 1987.  相似文献   

18.
In this paper we consider derivations in the (&, )-fragment of the intuitionistic propositional calculus. As is known, replacement of any occurrence of a formula [F] in a sequent S by an occurrence of the formula [p], where p is a new propositional variable, with the simultaneous addition to the antecedent of the formula F p or p F depending on the sign of the occurrence of F in S, leaves the derivability unchanged. We give a proof of the fact that the natural extension of this transformation to derivations preserves the relation of equivalence of derivations, i.e., transformed derivations are equivalent if and only if the originals are equivalent. (Derivations are considered equivalent if certain of their normal forms coincide, or, what is the same, if their deductive terms coincide.) It is proved that by the iteration of this transformation, each derivation of an arbitrary sequent S can be transformed into a derivation of a sequent S, depending only on S, whose succedent is a variable, and in the antecedent there occur only formulas of the form a,a & b, a b,,(a b) c, a & b c, a (b & c), wherea, b, c are variables. Here if S is balanced, then S is also balanced. (A sequent is called balanced if each variable occurs in it no more than twice.) The familiar correspondence between certain concepts of the theory of categories and concepts of the theory of proofs allows one to assert that there has been constructed a univalent functor, mapping a free Cartesian closed category into itself.Translated from Zapiski Nauchnykh Seminarov Leningradskogo Otdeleniya Matematicheskogo Instituta im. V. A. Steklova AN SSSR, Vol. 88, pp. 197–207, 1979.  相似文献   

19.
20.
Sufficient conditions are obtained in terms of matrix elements for the boundedness of Lebesgue functions of linear methods of summation of expansions in orthogonal systems of polynomial type.Translated from Matematicheskie Zametki, Vol. 6, No. 3, pp. 277–286, September, 1969.  相似文献   

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