Families of simple Jacobians with many automorphisms

We study an explicit ( $2 g-1$ )-dimensional family of Jacobian varieties of dimension $\frac{1}{2}(d-1)(g-1)$, arising from quotient curves of unramified cyclic coverings of prime degree $d$ of hyperelliptic curves of genus $g \geqslant 2$. By using a deformation argument, we prove that the generic...

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Detalles Bibliográficos
Autores: Naranjo del Val, Juan Carlos, Ortega, Angela, Pirola, Gian Pietro, Spelta, Irene
Tipo de recurso: artículo
Estado:Versión publicada
Fecha de publicación:2025
País:España
Institución:Universidad de Oviedo (UNIOVI)
Repositorio:Dipòsit Digital de la UB
OAI Identifier:oai:diposit.ub.edu:2445/224822
Acceso en línea:https://hdl.handle.net/2445/224822
Access Level:acceso abierto
Palabra clave:Formes de Jacobi
Varietats abelianes
Jacobi forms
Abelian varieties
Descripción
Sumario:We study an explicit ( $2 g-1$ )-dimensional family of Jacobian varieties of dimension $\frac{1}{2}(d-1)(g-1)$, arising from quotient curves of unramified cyclic coverings of prime degree $d$ of hyperelliptic curves of genus $g \geqslant 2$. By using a deformation argument, we prove that the generic element of the family is simple. Furthermore, we completely describe their endomorphism algebra, and we show that they admit a rank $\frac{1}{2}(d-1)-1$ group of non-polarized automorphisms. As an application of these results, we prove the generic injectivity of the Prym map for étale cyclic coverings of hyperelliptic curves of odd prime degree under some slight numerical restrictions. This result generalizes in several directions previous results on genus 2 .