RUS  ENG
Full version
JOURNALS // Doklady Rossijskoj Akademii Nauk. Mathematika, Informatika, Processy Upravlenia // Archive

Dokl. RAN. Math. Inf. Proc. Upr., 2023 Volume 513, Pages 66–70 (Mi danma417)

MATHEMATICS

On the finiteness of the set of generalized Jacobians with nontrivial torsion points over algebraic number fields

V. P. Platonovab, V. S. Zhgoonacd, G.V. Fedorovae

a Federal State Institution Scientific Research Institute for System Analysis of the Russian Academy of Sciences, Moscow, Russian Federation
b Steklov Mathematical Institute of Russian Academy of Sciences, Moscow, Russian Federation
c National Research University Higher School of Economics, Moscow, Russian Federation
d Moscow Institute of Physics and Technology (National Research University), Moscow, Russian Federation
e Lomonosov Moscow State University, Moscow, Russian Federation

Abstract: For a smooth projective curve $\mathcal{C}$ defined over algebraic number field $k$, we investigate the question of finiteness of the set of generalized Jacobians $J_m$ of a curve $\mathcal{C}$ associated with modules $m$ defined over $k$ such that a fixed divisor representing a class of finite order in the Jacobian $J$ of the curve $\mathcal{C}$ provides the torsion class in the generalized Jacobian $J_m$. Various results on the finiteness and infiniteness of the set of generalized Jacobians with the above property are obtained depending on the geometric conditions on the support of $m$, as well as on the conditions on the field $k$. These results were applied to the problem of the periodicity of a continuous fraction decomposition constructed in the field of formal power series $k((1/x))$, for the special elements of the field of functions $k(\tilde{\mathcal{C}})$ of the hyperelliptic curve $\tilde{\mathcal{C}}:y^2=f(x)$.

Keywords: Jacobian variety, generalized Jacobian, torsion points, continuous fractions, hyperelliptic curve.

UDC: 511.6

Received: 11.09.2023
Revised: 20.09.2023
Accepted: 05.10.2023

DOI: 10.31857/S2686954323700285


 English version:
Doklady Mathematics, 2023, 108:2, 382–386

Bibliographic databases:


© Steklov Math. Inst. of RAS, 2024