On the torsion of Drinfeld modules of rank two
On the torsion of Drinfeld modules of rank two
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关于二阶 Drinfeld 模的扭转
DOI:
10.1515/crelle.2010.017
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发表时间:
2007
期刊:
影响因子:
--
通讯作者:
Ambrus Pál
中科院分区:
文献类型:
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作者:
Ambrus Pál
Abstract We prove that the curve Y 0(?) has no ?2(T)-rational points where ? ⊲ ?2[T] is a prime ideal of degree at least 3 and Y 0(?) is the affine Drinfeld modular curve parameterizing Drinfeld modules of rank two over ?2[T] of generic characteristic with Hecke-type level ?-structure. As a consequence we derive a conjecture of Schweizer describing completely the torsion of Drinfeld modules of rank two over ?2(T) implying the uniform boundedness conjecture in this particular case. We reach our results with a variant of the formal immersion method. Moreover we show that the group Aut(X 0(?)) has order two. As a further application of our methods we also determine the prime-to-p cuspidal torsion packet of X 0(?) where ? ⊲ ? q [T] is a prime ideal of degree at least 3 and q is a power of the prime p.