共查询到7条相似文献,搜索用时 0 毫秒
1.
Yasutsugu Fujita Tetsuo Nakamura 《Transactions of the American Mathematical Society》2007,359(11):5505-5515
Let be an elliptic curve over a number field and its -isogeny class. We are interested in determining the orders and the types of torsion groups in . For a prime , we give the range of possible types of -primary parts of when runs over . One of our results immediately gives a simple proof of a theorem of Katz on the order of maximal -primary torsion in .
2.
We study elliptic surfaces corresponding to an equation of the specific type , defined over the finite field for a prime power . It is shown that if defines a curve that is maximal over then the rank of the group of sections defined over on the elliptic surface is determined in terms of elementary properties of the rational function . Similar results are shown for elliptic surfaces given by using prime powers and curves . Finally, for each of the forms used here, existence of curves with the property that they are maximal over is discussed, as well as various examples. 相似文献
3.
Xinqiang Qin Gang Hu Yang Yang Guo Wei 《Mathematical Methods in the Applied Sciences》2016,39(6):1336-1348
Quartic C‐Bézier curves possess similar properties with the traditional Bézier curves including terminal property, convex hull property, affine invariance, and approaching the shape of their control polygons as the shape parameter α decreases. In this paper, by adjusting the shape parameter α on the basis of the utilization of the least square approximation and nonlinear functional minimization together with fairing of a quartic C‐Bézier curve with G1 continuity of quartic C‐Bézier curve segments, we develop a fairing and G1 continuity algorithm for any given stitching coefficients λk(k = 1,2,…,n ? 1). The shape parameters αi(i=1, 2, …, n) can be adjusted by the value of control points. The curvature of the resulting quartic C‐Bézier curve segments after fairing is more uniform than before. Moreover, six examples are provided in the paper to demonstrate the efficacy of the algorithm and illustrate how to apply this algorithm to the computer‐aided design/computer‐aided manufacturing modeling systems. Copyright © 2015 John Wiley & Sons, Ltd. 相似文献
4.
Joseph H. Silverman. 《Mathematics of Computation》1999,68(226):835-858
Let be an elliptic curve of rank 1. We describe an algorithm which uses the value of and the theory of canonical heghts to efficiently search for points in and . For rank 1 elliptic curves of moderately large conductor (say on the order of to ) and with a generator having moderately large canonical height (say between 13 and 50), our algorithm is the first practical general purpose method for determining if the set contains non-torsion points.
5.
Two different approaches to the solutions of boundary value problems in mathematical physics are discussed. First, a theoretical model based on an ideal model. The second approach is based on experimental data and a suitable approximation scheme. 相似文献
6.
Hwang et al. proposed their generalization of proxy signature schemes based on elliptic curves. However, two attacks are proposed to show that their schemes have serious security flaws. By the first attack, an adversary can forge an illegal proxy signature that verifiers cannot actually find out the original signers of proxy signatures. The second attack is used to change proxy signatures into multi-signatures belonging to the group that actually generates the proxy signatures. To overcome these flaws, our improvement on Hwang et al.’s scheme is also proposed. 相似文献
7.
Yongqiao Wang Donghe Pei Xiupeng Cui 《Mathematical Methods in the Applied Sciences》2017,40(18):7151-7161
We introduce the notions of the pseudospherical normal Darboux images for the curve on a lightlike surface in Minkowski 3‐space and study these Darboux images by using technics of the singularity theory. Furthermore, we give a relation between these Darboux images and Darboux frame from the viewpoint of Legendrian dualities. 相似文献