English

Constant Tamagawa numbers of special elliptic curves

Number Theory 2021-06-02 v1

Abstract

For the elliptic curves Eσ2D:y2=x3+σ2DxE_{\sigma 2D} : y^2 = x^3 + \sigma 2Dx , which has 2-isogeny curve Eσ2D:y2=x3σ8DxE'_{\sigma 2D} : y^2 = x^3 -\sigma 8Dx, σ=±1, D=p1e1p2e2pnen\sigma = \pm 1,\ D = p_1^{e_1}p_2^{e_2}\cdots p_n^{e_n}, where pip_i are different odd prime numbers and ei=1 or 3e_i = 1 \text{ or } 3, we demonstrate that Tamagawa numbers of these elliptic curves are always one or zero by the use of matrix in finite field F2\mathbb F_2. The specific number depends on the value of σ\sigma. By our proofs of these results, we find a method to quickly sieve a part of the elliptic curves with Mordell-Weil rank zero or rank one in this form as an application.

Keywords

Cite

@article{arxiv.2106.00340,
  title  = {Constant Tamagawa numbers of special elliptic curves},
  author = {Luying Li and Chang Lv},
  journal= {arXiv preprint arXiv:2106.00340},
  year   = {2021}
}