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Generic reconstruction of rational maps from multipliers of periods one and two
Abstract
For every integer d≥2 and every field of characteristic different from $2$, we prove that on the moduli space ℳd of degree-d rational maps, the multiplier spectrum morphism formed from the periodic points of periods one and two is birational to the closure of its image. Consequently, over every algebraically closed field of characteristic different from $2$, it is generically injective, which proves a recent conjecture of Ji and Xie in characteristic zero. The proof uses a fixed-index normal form, a non-archimedean degeneration of two-cycles, and birational reconstruction of an affine fixed-point configuration from pair invariants.
Related
BibTeX
@misc{zhang2026generic,
title = {{Generic reconstruction of rational maps from multipliers of periods one and two}},
author = {Geng-Rui Zhang},
howpublished = {arXiv},
year = {2026},
month = sep,
doi = {10.48550/arxiv.2609.07383},
eprint = {2609.07383},
archivePrefix = {arXiv},
url = {https://arxiv.org/abs/2609.07383},
}
RIS
TY - UNPB
TI - Generic reconstruction of rational maps from multipliers of periods one and two
AU - Geng-Rui Zhang
PY - 2026
DA - 2026/09/07
PB - arXiv
DO - 10.48550/arxiv.2609.07383
UR - https://arxiv.org/abs/2609.07383
AB - For every integer d≥2 and every field of characteristic different from $2$, we prove that on the moduli space ℳ_d of degree-d rational maps, the multiplier spectrum morphism formed from the periodic points of periods one and two is birational to the closure of its image. Consequently, over every algebraically closed field of characteristic different from $2$, it is generically injective, which proves a recent conjecture of Ji and Xie in characteristic zero. The proof uses a fixed-index normal form, a non-archimedean degeneration of two-cycles, and birational reconstruction of an affine fixed-point configuration from pair invariants.
ER -