Explicit Arithmetic of Jacobians of Generalized Legendre Curves Over Global Function Fields
Explicit Arithmetic of Jacobians of Generalized Legendre Curves Over Global Function Fields
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全局函数域上广义勒让德曲线雅可比行列式的显式算术
DOI:
10.1090/memo/1295
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发表时间:
2020
期刊:
影响因子:
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通讯作者:
Ulmer, Douglas
中科院分区:
文献类型:
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作者:
Berger, Lisa;Hall, Chris;Pannekoek, René;Park, Jennifer;Pries, Rachel;Sharif, Shahed;Silverberg, Alice;Ulmer, Douglas
We study the Jacobian J of the smooth projective curve C of genus r− 1 with affine model yr= xr− 1 (x+ 1)(x+ t) over the function field Fp (t), when p is prime and r≥ 2 is an integer prime to p. When q is a power of p and d is a positive integer, we compute the L-function of J over Fq (t1/d) and show that the Birch and Swinnerton-Dyer conjecture holds for J over Fq (t1/d). When d is divisible by r and of the form pν+ 1, and Kd:= Fp (μd, t1/d), we write down explicit points in J (Kd), show that they generate a subgroup V of rank (r− 1)(d− 2) whose index in J (Kd) is finite and a power of p, and show that the order of the Tate-Shafarevich group of J over Kd is [J (Kd): V] 2. When r> 2, we prove that the “new” part of J is isogenous over Fp (t) to the square of a simple abelian variety of dimension φ (r)/2 with endomorphism algebra Z [μr]+. For a prime l with l pr, we prove that J [l](L)={0} for any abelian extension L of Fp (t).