English

Rigidity of Lyapunov exponents for polynomials

Dynamical Systems 2026-03-24 v1 Algebraic Geometry Number Theory

Abstract

Let f,gQ[z]f,g\in\overline{\mathbb{Q}}[z] be polynomials of degree d2d\geq2 with disconnected Julia sets. We prove that they have the same Lyapunov exponent Lf=Lg\mathcal{L}_f=\mathcal{L}_g if and only if either ff and gg are intertwined, or ff and g\overline{g} are intertwined. The analogous result for critical heights is also obtained. As an application, we provide a new proof of the theorem stating that the multiplier spectrum morphism on the moduli space of polynomials is generically injective.

Keywords

Cite

@article{arxiv.2603.21179,
  title  = {Rigidity of Lyapunov exponents for polynomials},
  author = {Zhuchao Ji and Junyi Xie and Geng-Rui Zhang},
  journal= {arXiv preprint arXiv:2603.21179},
  year   = {2026}
}

Comments

15 pages

R2 v1 2026-07-01T11:32:05.544Z