English

Expander graphs, gonality and variation of Galois representations

Number Theory 2019-12-19 v4

Abstract

We show that families of coverings of an algebraic curve where the associated Cayley-Schreier graphs form an expander family exhibit strong forms of geometric (genus and gonality) growth. Combining this general result with finiteness statements for rational points under such conditions, we derive results concerning the variation of Galois representations in one-parameter families of abelian varieties.

Keywords

Cite

@article{arxiv.1008.3675,
  title  = {Expander graphs, gonality and variation of Galois representations},
  author = {Jordan Ellenberg and Chris Hall and Emmanuel Kowalski},
  journal= {arXiv preprint arXiv:1008.3675},
  year   = {2019}
}

Comments

32 pages; v4: changes mostly in exposition