English

A sparsity result for the Dynamical Mordell-Lang Conjecture in positive characteristic

Number Theory 2020-12-29 v1

Abstract

We prove a quantitative partial result in support of the Dynamical Mordell-Lang Conjecture (also known as the DML conjecture) in positive characteristic. More precisely, we show the following: given a field KK of characteristic pp, given a semiabelian variety XX defined over a finite subfield of KK and endowed with a regular self-map Φ:XX\Phi:X \longrightarrow X defined over KK, given a point αX(K)\alpha\in X(K) and a subvariety VXV\subseteq X, then the set of all non-negative integers nn such that Φn(α)V(K)\Phi^n(\alpha)\in V(K) is a union of finitely many arithmetic progressions along with a subset SS with the property that there exists a positive real number AA (depending only on NN, Φ\Phi, α\alpha, VV) such that for each positive integer MM, we have #{nS ⁣: nM}A(1+logM)dimV.\#\left\{n\in S\colon~ n\le M\right\}\le A\cdot \left(1+\log M\right)^{\dim V}.

Keywords

Cite

@article{arxiv.2012.13711,
  title  = {A sparsity result for the Dynamical Mordell-Lang Conjecture in positive characteristic},
  author = {Dragos Ghioca and Alina Ostafe and Sina Saleh and Igor E. Shparlinski},
  journal= {arXiv preprint arXiv:2012.13711},
  year   = {2020}
}