English

Higher congruence companion forms

Number Theory 2013-04-12 v4

Abstract

For a rational prime p3p \geq 3 we consider pp-ordinary, Hilbert modular newforms ff of weight k2k\geq 2 with associated pp-adic Galois representations ρf\rho_f and modpn\mod{p^n} reductions ρf,n\rho_{f,n}. Under suitable hypotheses on the size of the image, we use deformation theory and modularity lifting to show that if the restrictions of ρf,n\rho_{f,n} to decomposition groups above pp split then ff has a companion form gg modulo pnp^n (in the sense that ρf,nρg,nχk1\rho_{f,n}\sim \rho_{g,n}\otimes\chi^{k-1}).

Keywords

Cite

@article{arxiv.1007.0181,
  title  = {Higher congruence companion forms},
  author = {Rajender Adibhatla and Jayanta Manoharmayum},
  journal= {arXiv preprint arXiv:1007.0181},
  year   = {2013}
}

Comments

13 pages

R2 v1 2026-06-21T15:43:30.853Z