Resumen de Structure of the cuspidal rational torsion subgroup of J1(pn)

Yifan Yang, Jeng-Daw Yu

• Let p be a prime and let J1(pn) denote the Jacobian of the modular curve X1(pn). The Jacobian J1(pn) contains a Q-rational torsion subgroup generated by the cuspidal divisor classes [(a/pn) .

  (��)], where p  a. In this paper, we determine the structure of the p-primary subgroup of this Q-rational torsion subgroup in the case where p is a regular prime.