English

On upper bounds of arithmetic degrees

Algebraic Geometry 2018-02-12 v3 Dynamical Systems Number Theory

Abstract

Let XX be a smooth projective variety over Q \overline{\mathbb Q}, and f:XrightarrowXf:X -rightarrow X be a dominant rational map. Let δf\delta_{f} be the first dynamical degree of ff and hX:X(Q)[1,)h_{X}:X( \overline{\mathbb Q})\to [1,\infty) be a Weil height function on XX associated with an ample divisor on XX. We prove several inequalities which give upper bounds of the sequence (hX(fn(P)))n0(h_X (f^n(P)))_{n\geq0} where PP is a point of X(Q)X( \overline{\mathbb Q}) whose forward orbit by ff is well-defined. As a corollary, we prove that the upper arithmetic degree is less than or equal to the first dynamical degree; αf(P)δf \overline{\alpha}_{f}(P) \leq \delta_{f}. Furthermore, if the Picard number of XX is one, ff is algebraically stable and δf>1\delta_{f}>1, we prove that the limit defining canonical height limnhX(fn(P))/δfn\lim_{n\to \infty} h_{X} (f^{n}(P)) \big/ \delta_f^n converges.

Keywords

Cite

@article{arxiv.1606.00598,
  title  = {On upper bounds of arithmetic degrees},
  author = {Yohsuke Matsuzawa},
  journal= {arXiv preprint arXiv:1606.00598},
  year   = {2018}
}
R2 v1 2026-06-22T14:15:43.147Z