共查询到19条相似文献,搜索用时 171 毫秒
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Abderrahmane Nitaj 《计算数学(英文版)》2002,20(4):337-348
AbstractAn elliptic curve is a pair (E,O), where ?is a smooth projective curve of genus 1 and O is a point of E, called the point at infinity. Every elliptic curve can be given by a Weierstrass equationE:y2 a1xy a3y = x3 a2x2 a4x a6.Let Q be the set of rationals. E is said to be dinned over Q if the coefficients ai, i = 1,2,3,4,6 are rationals and O is defined over Q.Let E/Q be an elliptic curve and let E(Q)tors be the torsion group of points of E denned over Q. The theorem of Mazur asserts that E(Q)tors is one of the following 15 groupsE(Q)tors Z/mZ, m = 1,2,..., 10,12,Z/2Z × Z/2mZ, m = 1,2,3,4.We say that an elliptic curve E'/Q is isogenous to the elliptic curve E if there is an isogeny, i.e. a morphism : E E' such that (O) = O, where O is the point at infinity.We give an explicit model of all elliptic curves for which E(Q)tors is in the form Z/mZ where m= 9,10,12 or Z/2Z × Z/2mZ where m = 4, according to Mazur's theorem. Morever, for every family of such elliptic curves, we give an explicit m 相似文献
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确定了一类中心循环的有限p-群G的自同构群.设G=X_3(p~m)~(*n)*Z_(p~(m+r)),其中m≥1,n≥1和r≥0,并且X_3(p~m)=x,y|x~(p~m)=y~(p~m)=1,[x,y]~(p~m)=1,[x,[x,y]]=[y,[x,y]]=1.Aut_nG表示Aut G中平凡地作用在N上的元素形成的正规子群,其中G'≤N≤ζG,|N|=p~(m+s),0≤s≤r,则(i)如果p是一个奇素数,那么AutG/Aut_nG≌Z_(p~((m+s-1)(p-1))),Aut_nG/InnG≌Sp(2n,Z_(p~m))×Z_(p~(r-s)).(ii)如果p=2,那么AutG/Aut_nG≌H,其中H=1(当m+s=1时)或者Z_(2~(m+s-2))×Z_2(当m+s≥2时).进一步地,Aut_nG/InnG≌K×L,其中K=Sp(2n,Z_(2~m))(当r0时)或者O(2n,Z_(2~m))(当r=0时),L=Z_(2~(r-1))×Z_2(当m=1,s=0,r≥1时)或者Z_(2~(r-s)). 相似文献
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A题组新编1.已知⊙C:(x+3)2+y2=R2(R>0)和⊙D:(x-3)2+y2=1,动圆M与⊙C,⊙D均相切,圆心M的轨迹为E.(1)当R=1时,E的方程是;(2)当R=3时,E的方程是;(3)当R=5时,E的方程是;(4)当R=7时,E的方程是;(5)当R=9时,E的方程是.2.已知:椭圆:x225+y216=1,F1、F2分别为左、右焦点,点A(1,m),点P为椭圆上动点.(1)当m=5时,|PA|+|PF2|的最小值是;(2)当m=1时,|PA|+53|PF2|的最小值是;(3)当m=1时,|PA|+|PF2|的最小值是.3.△ABC中,三个顶点的坐标分别为A(2,4),B(-1,2),C(1,0),点P(x,y)在△ABC内部及边界运动,(1)z=ax-y取最小值的唯一最优解是(-1… 相似文献
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In this paper, the automorphism group of a generalized extraspecial p-group G is determined, where p is a prime number. Assume that |G| = p 2n+m and |ζG| = p m , where n 1 and m 2. (1) When p is odd, let Aut G G = {α∈ AutG | α acts trivially on G }. Then Aut G G⊿AutG and AutG/Aut G G≌Z p-1 . Furthermore, (i) If G is of exponent p m , then Aut G G/InnG≌Sp(2n, p) × Z p m-1 . (ii) If G is of exponent p m+1 , then Aut G G/InnG≌ (K Sp(2n-2, p))×Z p m-1 , where K is an extraspecial p-group of order p 2n-1 . In particular, Aut G G/InnG≌ Z p × Z p m-1 when n = 1. (2) When p = 2, then, (i) If G is of exponent 2 m , then AutG≌ Sp(2n, 2) × Z 2 × Z 2 m-2 . In particular, when n = 1, |AutG| = 3 · 2 m+2 . None of the Sylow subgroups of AutG is normal, and each of the Sylow 2-subgroups of AutG is isomorphic to H K, where H = Z 2 × Z 2 × Z 2 × Z 2 m-2 , K = Z 2 . (ii) If G is of exponent 2 m+1 , then AutG≌ (I Sp(2n-2, 2)) × Z 2 × Z 2 m-2 , where I is an elementary abelian 2-group of order 2 2n-1 . In particular, when n = 1, |AutG| = 2 m+2 and AutG≌ H K, where H = Z 2 × Z 2 × Z 2 m-1 , K = Z 2 . 相似文献
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Let XH = {XH(s),s ∈RN1} and X K = {XK(t),t ∈R N2} be two independent anisotropic Gaussian random fields with values in R d with indices H =(H1,...,HN1) ∈(0,1)N1,K =(K1,...,KN2) ∈(0,1) N2,respectively.Existence of intersections of the sample paths of X H and X K is studied.More generally,let E1■RN1,E2■RN2 and FRd be Borel sets.A necessary condition and a sufficient condition for P{(XH(E1)∩XK(E2))∩F≠Ф}>0 in terms of the Bessel-Riesz type capacity and Hausdorff measure of E1×E2×F in the metric space(RN1+N2+d,) are proved,where is a metric defined in terms of H and K.These results are applicable to solutions of stochastic heat equations driven by space-time Gaussian noise and fractional Brownian sheets. 相似文献
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Let RN (N 2, N = n or m) be the N-dimensional Euclidean space and SN-1 be the unitsphere in RN. For nonzero point x RN, we denote x' = x/ |x|. E. M. Stein[12] defined a highdimensional analogue of the Marcinkiewicz integral on Rn by (f)(x)= (R|Fs(x)|2ds)1/2,where Fs(x) =dv, is a homogeneous function of degree zero, whoserestriction to Sn-1 is in L1 (Sn-1) and satisfies the cancellation property sn-1 (x')dx'= 0. Itis well-known that the Marcinkiewicz integral is very useful in harmonic… 相似文献
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对称自正交相似矩阵逆特征值问题的推广 总被引:1,自引:0,他引:1
陈邦考 《高等学校计算数学学报》2006,28(3):283-288
1引言对称自正交相似矩阵在结构力学、土木工程、数值分析等方面有实际应用,不少问题中常会遇到其逆特征值同题,研究它是有应用价值的.记(?)其中E=E_m(m阶单位阵).容易验证1)T_k(E)·T_k(E)=E_(km).2)T′_k(E)=T_k(E),其中T′_k(E)表示T_k(E)的转置.3) (?)其中k∈N(自然数).令(?)当m=1时,T_k(E)就是k阶反序单位矩阵,即文[1]的(1)和(2).定义1.1设A∈R~(2km×2km)满足SAS′=A,A′=A,则称A为对称自正交相似矩 相似文献
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《中学生数学》2004年3月上(高中版第3期)给出了~3(1/2)是无理数的证明,但过程繁琐.现给出它的简捷证法. 证明用反证法:假设~3(1/2)是有理数,则可设~3(1/2)=m/n(m∈Z,n∈N )且m,n互质. ∴3=m2/n2(?)m2=3n2, ∴m必为3的倍数,可设m=3k(k∈Z), 相似文献
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In this paper, we introduce Property ∏σ of operator algebras and prove that nest subalgebras and the finite-width CSL subalgebras of arbitrary von Neumann algebras have Property ∏σ.Finally, we show that the tensor product formula alg ML1-(×)algNL2 = algM-(×)N(L1 (×) L2) holds for any two finite-width CSLs L1 and L2 in arbitrary von Neumann algebras M and N, respectively. 相似文献
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若G1和G2是两个图,G1和G2的Kronecker图定义为V (G1×G2)= V (G1) × V (G2 E(G1 × G2)= {(u1,v1)(u2,v2)。在本文中,我们计算了p-部完全图 m1,m2,...,mp 和完全图Kn 的Kronecker积的顶点参数,m1 ≤ m2 ≤ ... ≤ mp,2 ≤ p ≤ n, and n ≥ 3 ,扩展了Mamut和Vumar的相关结论[Inform. Process. Lett. 106(2008)258-262]. 相似文献
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本文首先将Hal定理推广为:设N为G的正规子群,若N为Enπ群,G/N为Dπ群,则G为Dπ群.在此基础上得到了群G为Enπ群的充要条件为:(1)G存在正规子群N,满足N及G/N为Enπ群;(2)对任意p∈π,任意q∈π {p}及任意p 元素x,CG(x)含G的Sylowq 子群.另外,我们对非Able单群的情形也进行了一些讨论. 相似文献
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A. Yu. Solynin 《Journal of Mathematical Sciences》1987,38(4):2140-2142
Let be the family of all continua E in
, where U={¦z¦ < 1}, let U(E) be the connected component of UE containing the point z=0, let wE(z0=w(z0, E, U(E)) be the harmonic measure of E relative to the domain U(E) at the point z0 U(E). In the paper one answers affirmatively a question raised by B. Rodkin [K. F. Barth, D. A. Branna, and W. K. Hayman, Research problems in complx analysis, Bull. London Math. Soc.,l6, No. 5, 490–517, 1984]. Namely, one proves that in the family (d0) of continua E , satisfying the condition diam E=d0,o<d02, one has the inequality
arcsin d0/2, one indicates all the cases for which equality prevails.Translated from Zapiski Nauchnykh Seminarov Leningradskogo Otdeleniya Matematicheskogo Instituta im. V. A. Steklova AN SSSR, Vol. 144, pp. 146–148, 1985. 相似文献
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Aleksandra S.Kosti 《Algebra Colloquium》2021,28(4):625-634
Let R be an associative unital ring and not necessarily commutative.We analyze conditions under which every n × n matrix A over R is expressible as a sum A =E1 +…+ Es + N of (commuting) idempotent matrices Ei and a nilpotent matrix N. 相似文献