English

Unramifiedness of Galois representations arising from Hilbert modular surfaces

Number Theory 2017-10-31 v4

Abstract

Let pp be a prime number and FF a totally real number field. For each prime p\mathfrak{p} of FF above pp we construct a Hecke operator TpT_\mathfrak{p} acting on (modpm)(\mathrm{mod}\, p^m) Katz Hilbert modular classes which agrees with the classical Hecke operator at p\mathfrak{p} for global sections that lift to characteristic zero. Using these operators and the techniques of patching complexes of F. Calegari and D. Geraghty we prove that the Galois representations arising from torsion Hilbert modular classes of parallel weight 1{\bf 1} are unramified at pp when [F:Q]=2[F:\mathbb Q]=2. Some partial and some conjectural results are obtained when [F:Q]>2[F:\mathbb Q]>2.

Keywords

Cite

@article{arxiv.1410.6203,
  title  = {Unramifiedness of Galois representations arising from Hilbert modular surfaces},
  author = {Matthew Emerton and Davide A. Reduzzi and Liang Xiao},
  journal= {arXiv preprint arXiv:1410.6203},
  year   = {2017}
}

Comments

Final version, to appear in Forum Sigma