English

On a simple model of X_0(N)

Number Theory 2017-04-05 v1

Abstract

We find plane models for all X0(N)X_0(N), N2N\geq 2. We observe a map from the modular curve X0(N)X_0(N) to the projective plane constructed using modular forms of weight 1212 for the group Γ0(N)\Gamma_0(N); the Ramanujan function Δ\Delta, Δ(N)\Delta(N\cdot) and the third power of Eisestein series of weight 44, E43E_4^3, and prove that this map is birational equivalence for every N2N\geq 2. The equation of the model is the minimal polynomial of Δ(N)/Δ\Delta(N\cdot)/\Delta over C(j)\mathbb{C}(j).

Cite

@article{arxiv.1704.01098,
  title  = {On a simple model of X_0(N)},
  author = {Iva Kodrnja},
  journal= {arXiv preprint arXiv:1704.01098},
  year   = {2017}
}
R2 v1 2026-06-22T19:07:32.583Z