Arithmetic exceptionality of Latt\`{e}s maps
Number Theory
2026-03-27 v1
Abstract
Let denote a finite field of order . A rational function is said to be arithmetically exceptional if it induces a permutation on for infinitely many primes . Based on some computational results, Odaba\c{s} conjectured that for each , the -th Latt\`{e}s map attached to an elliptic curve is arithmetically exceptional if and only if has no -torsion point whose -coordinate is rational. In this paper, we prove that this conjecture is true for any elliptic curve having complex multiplication by an imaginary quadratic field other than On the other hand, we show that the conjecture becomes invalid if has CM by and . Partial results for non-CM elliptic curves are also given.
Cite
@article{arxiv.2603.25014,
title = {Arithmetic exceptionality of Latt\`{e}s maps},
author = {Chatchawan Panraksa and Detchat Samart and Songpon Sriwongsa},
journal= {arXiv preprint arXiv:2603.25014},
year = {2026}
}
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22 pages