Bielliptic smooth plane curves and quadratic points

Let Ck be a smooth plane curve of degree d ≥ 4 defined over a global field k of characteristic p = 0 or p > (d-1)(d-2)/2 (up to an extra condition on Jac(Ck)). Unless the curve is bielliptic of degree four, we observe that it always admits finitely many quadratic points. We further show that ther...

Descripción completa

Detalles Bibliográficos
Autores: Badr, Eslam|||0000-0002-3960-7243, Bars Cortina, Francesc|||0000-0003-4779-3995
Tipo de recurso: artículo
Fecha de publicación:2021
País:España
Institución:Universitat Autònoma de Barcelona
Repositorio:Dipòsit Digital de Documents de la UAB
Idioma:inglés
OAI Identifier:oai:ddd.uab.cat:240649
Acceso en línea:https://ddd.uab.cat/record/240649
https://dx.doi.org/urn:doi:10.1142/S1793042121500238
Access Level:acceso abierto
Palabra clave:Plane curves
Bielliptic curves
Automorphism group
Twist
Descripción
Sumario:Let Ck be a smooth plane curve of degree d ≥ 4 defined over a global field k of characteristic p = 0 or p > (d-1)(d-2)/2 (up to an extra condition on Jac(Ck)). Unless the curve is bielliptic of degree four, we observe that it always admits finitely many quadratic points. We further show that there are only finitely many quadratic extensions k(√D) when k is a number field, in which we may have more points of Ck than these over k. In particular, we have this asymptotic phenomenon valid for Fermat's and Klein's equations. Second, we conjecture that there are two infinite sets E and D of isomorphism classes of smooth projective plane quartic curves over k with a prescribed automorphism group, such that all members of E (respectively, D) are bielliptic and have finitely (respectively, infinitely) many quadratic points over a number field k. We verify the conjecture over k = Q for G = Z/6Z and GAP(16, 13). The analog of the conjecture over global fields with p > 0 is also considered.