English

Polylogarithms for $GL_2$ over totally real fields

Number Theory 2016-04-15 v1

Abstract

We give a new, purely topological construction of Eisenstein cohomology classes for Hilbert-Blumenthal varieties using the polylogarithm for families of topological tori and a decomposition with respect to the units in the center of GL2GL_2. These classes are explicitly calculated in de Rham chomology and compared with Harder's Eisenstein classes. For non-trivial coefficient systems the whole Eisenstein cohomology in positive degrees is generated by these topological Eisenstein classes. This gives an alternative proof for the rationality of Harder's Eisenstein operator without using any multiplicity one arguments. The text constitutes my 2016 Regensburg PhD thesis.

Keywords

Cite

@article{arxiv.1604.04209,
  title  = {Polylogarithms for $GL_2$ over totally real fields},
  author = {Philipp Graf},
  journal= {arXiv preprint arXiv:1604.04209},
  year   = {2016}
}
R2 v1 2026-06-22T13:32:38.924Z