2023/12/20 by Laga, Jef, Shnidman, Ari · 2 citations
#14C25 (Primary) 14H40 #14H45 (Secondary) #Algebraic Geometry (math.AG) #FOS: Mathematics #Number Theory (math.NT)
paper · doi:10.48550/arxiv.2312.12965
We show that the Ceresa cycle κ(Ct) of the genus 3 curve Ct \colon y3 = x4 + 2tx2 + 1 is torsion if and only if Qt=( √[3]t2 -1,t) is a torsion point on the elliptic curve y2 = x3 + 1. This shows that there are infinitely many smooth plane quartic curves over ℂ (resp. ℚ) with torsion (resp. infinite order) Ceresa cycle. Over ℚ, we show that the Beilinson--Bloch height of κ(Ct) is proportional to the Neron--Tate height of Qt. Thus, the height of κ(Ct) is nondegenerate and satisfies a Northcott property. To prove all this, we show that the Chow motive that controls κ(Ct) is isomorphic to \mathfrakh1 of an appropriate elliptic curve.