# Rational torsion of generalized Jacobians of modular and Drinfeld modular curves

Fu Tsun Wei, Takao Yamazaki

## 抄録

We consider the generalized Jacobian J of the modular curve X 0 (N) of level N with respect to a reduced divisor consisting of all cusps. Supposing N is square free, we explicitly determine the structure of the Q-rational torsion points on J up to 6-primary torsion. The result depicts a fuller picture than [18] where the case of prime power level was studied. We also obtain an analogous result for Drinfeld modular curves. Our proof relies on similar results for classical Jacobians due to Ohta, Papikian and the first author. We also discuss the Hecke action on J and its Eisenstein property.

本文言語 English 647-659 13 Forum Mathematicum 31 3 https://doi.org/10.1515/forum-2018-0141 Published - 2019 5 1

• 数学 (全般)
• 応用数学

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