English

Supercuspidal ramifications and traces of adjoint lifts at good primes

Number Theory 2019-03-21 v3

Abstract

In this paper, we write down the local Brauer classes of the endomorphism algebras of motives attached to non-CM primitive Hecke eigenforms for all supercuspidal primes in terms of traces of adjoint lifts at auxiliary primes. We give an alternative proof of the result for odd primes pp obtained in [MR3391026] and write down the ramification formulas for odd unramified supercuspidal primes of level zero also removing a mild hypothesis of [MR3391026]. We also give a complete description of ramifications for p=2p=2. The philosophy of adjoint lifts help us to determine the local Brauer classes at non dihedral primes by using results similar to [MR2770587]. We provide some numerical examples using {Sage} and {LMFDB} supporting some of our theorems.

Keywords

Cite

@article{arxiv.1712.05623,
  title  = {Supercuspidal ramifications and traces of adjoint lifts at good primes},
  author = {Debargha Banerjee and Tathagata Mandal},
  journal= {arXiv preprint arXiv:1712.05623},
  year   = {2019}
}