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arXiv 1301.0035math.NTcs.CR
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关于小Elkies素数的乘积

On the Product of Small Elkies Primes

Igor Shparlinski

摘要:

给定$E$的有限域$\F_q$上的椭圆曲线$E$,如果$t_E^2 - 4q$是模$\ell$的二次剩余,则称奇素数$\ell \nmid q$是$E$的Elkies素数,其中$t_E = q+1 - #E(\F_q)$和$#E(\F_q)$是$E$上$\F_q$ -有理点的个数.这些素数用于目前最有效的计算$#E(\F_q)$的算法中。特别地,使得$E$直到$L_q(E)$的所有Elkies素数的乘积超过$4q^{1/2}$的约束$L_q(E)$是该算法的关键参数。我们发现,有无穷多对$(p, E)$的素数$p$和曲线$E$在$\F_p$与$L_p(E) \ge c \log p \log \log \log p$的一些绝对常数$c>0$,而一个天真的启发式估计表明,$L_p(E) \sim \log p$。这补充了Galbraith和Satoh(2002)的最新结果,在广义黎曼假设下是有条件的,以及Shparlinski和Sutherland(2012)的最新结果,对几乎所有的对$(p,E)$都是无条件的。

英文摘要:

Given an elliptic curve $E$ over a finite field $\F_q$ of $q$ elements, we say that an odd prime $\ell \nmid q$ is an Elkies prime for $E$ if $t_E^2 - 4q$ is a quadratic residue modulo $\ell$, where $t_E = q+1 - #E(\F_q)$ and $#E(\F_q)$ is the number of $\F_q$-rational points on $E$. These primes are used in the presently most efficient algorithm to compute $#E(\F_q)$. In particular, the bound $L_q(E)$ such that the product of all Elkies primes for $E$ up to $L_q(E)$ exceeds $4q^{1/2}$ is a crucial parameter of this algorithm. We show that there are infinitely many pairs $(p, E)$ of primes $p$ and curves $E$ over $\F_p$ with $L_p(E) \ge c \log p \log \log \log p$ for some absolute constant $c>0$, while a naive heuristic estimate suggests that $L_p(E) \sim \log p$. This complements recent results of Galbraith and Satoh (2002), conditional under the Generalised Riemann Hypothesis, and of Shparlinski and Sutherland (2012), unconditional for almost all pairs $(p,E)$.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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