English

Equations involving the modular $j$-function and its derivatives

Complex Variables 2025-10-21 v3 Logic Number Theory

Abstract

We show that for any polynomial F(X,Y0,Y1,Y2)C[X,Y0,Y1,Y2]F(X,Y_0,Y_1,Y_2) \in \mathbb{C}[X, Y_0, Y_1, Y_2], the equation F(z,j(z),j(z),j(z))=0F(z,j(z),j'(z),j''(z))=0 has a Zariski dense set of solutions in the hypersurface F(X,Y0,Y1,Y2)=0F(X,Y_0,Y_1,Y_2)=0, unless FF is in C[X]\mathbb{C}[X] or it is divisible by Y0Y_0, Y01728Y_0-1728, or Y1Y_1. Our methods establish criteria for finding solutions to more general equations involving periodic functions. Furthermore, they produce a qualitative description of the distribution of these solutions.

Cite

@article{arxiv.2312.09974,
  title  = {Equations involving the modular $j$-function and its derivatives},
  author = {Vahagn Aslanyan and Sebastian Eterović and Vincenzo Mantova},
  journal= {arXiv preprint arXiv:2312.09974},
  year   = {2025}
}

Comments

37 pages; several typos corrected; appeared in J. Reine Angew. Math

R2 v1 2026-06-28T13:52:41.738Z