Work

The modular automorphisms of quotient modular curves

Year: 2025

Type: article

Abstract: We obtain the modular automorphism group of any quotient modular curve of level , with . In particular, we obtain some unexpected automorphisms of order 3 that appear for the quotient modular curves when the Atkin–Lehner involution belongs to the quotient modular group. We also prove that such automorphisms are not necessarily defined over . As a consequence of these results, we obtain the full automorphism group of the quotient modular curve , for sufficiently large .

Source: Mathematika

DOI: 10.1112/mtk.70065

Authors: Francesc Bars, Tarun Dalal

Institutions: Universitat Autònoma de Barcelona, Centre de Recerca Matemàtica, Beijing Institute of Mathematical Sciences and Applications

Language: English

Topic: Advanced Algebra and Geometry

Subfield: Mathematical Physics

Field: Mathematics

Domain: Physical Sciences

Open Access status: hybrid

Estimated APC paid: $3,930

Funders: Universitat Autònoma de Barcelona, Agencia Estatal de Investigación