An intriguing hyperelliptic Shimura curve quotient of genus 16
Abstract
Let be the maximal totally real subfield of , the cyclotomic field of nd roots of unity. Let be the quaternion algebra over ramified exactly at the unique prime above and 7 of the real places of . Let be a maximal order in , and the Shimura curve attached to . Let , where is the unique Atkin-Lehner involution on . We show that the curve has several striking features. First, it is a hyperelliptic curve of genus , whose hyperelliptic involution is exceptional. Second, there are Weierstrass points on , and exactly half of these points are CM points; they are defined over the Hilbert class field of the unique CM extension of class number contained in , the cyclotomic field of th roots of unity. Third, the normal closure of the field of -torsion of the Jacobian of is the Harbater field , the unique Galois number field unramified outside and , with Galois group . In fact, the Jacobian has the remarkable property that each of its simple factors has a -torsion field whose normal closure is the field . Finally, and perhaps the most striking fact about , is that it is also hyperelliptic over .
Keywords
Cite
@article{arxiv.1906.06772,
title = {An intriguing hyperelliptic Shimura curve quotient of genus 16},
author = {Lassina Dembele},
journal= {arXiv preprint arXiv:1906.06772},
year = {2021}
}
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