English

The $T$-adic Galois representation is surjective for a positive density of Drinfeld modules

Number Theory 2024-06-18 v1 Algebraic Geometry

Abstract

Let Fq\mathbb{F}_q be the finite field with q5q\geq 5 elements, A:=Fq[T]A:=\mathbb{F}_q[T] and F:=Fq(T)F:=\mathbb{F}_q(T). Assume that qq is odd and take |\cdot| to be the absolute value at \infty that is normalized by T=q|T|=q. Given a pair w=(g1,g2)A2w=(g_1, g_2)\in A^2 with g20g_2\neq 0, consider the associated Drinfeld module ϕw:AA{τ}\phi^w: A\rightarrow A\{\tau\} of rank 22 defined by ϕTw=T+g1τ+g2τ2\phi_T^w=T+g_1\tau+g_2\tau^2. Fix integers c1,c21c_1, c_2\geq 1 and define w:=max{g11c1,g21c2}|w|:=max\{|g_1|^{\frac{1}{c_1}}, |g_2|^{\frac{1}{c_2}}\}. I show that when ordered by height, there is a positive density of pairs w=(g1,g2)w=(g_1, g_2), such that the TT-adic Galois representation attached to ϕw\phi^w is surjective.

Keywords

Cite

@article{arxiv.2312.16796,
  title  = {The $T$-adic Galois representation is surjective for a positive density of Drinfeld modules},
  author = {Anwesh Ray},
  journal= {arXiv preprint arXiv:2312.16796},
  year   = {2024}
}