A new family of maximal curves not covered by the Hermitian curve
Abstract
For every prime power q and integer n≥1, we give a single Kummer equation defining an 𝔽q2n-maximal curve 𝒳q,n. The family recovers the Hermitian curves for n=1,2, the Giulietti--Korchmáros curve for n=3, and the Beelen--Montanucci curves for odd n≥5. For q>2 and even n≥4, it gives new maximal curves of genus (q2−1)qn/2 that are not covered by the Hermitian curve over 𝔽q2n. We compute the genus for both parities of n and give a uniform proof of maximality by counting rational places. For q>2 and odd n≥5, we remove the Galois hypothesis from the known non-covering results for the Beelen--Montanucci and Garcia--Güneri--Stichtenoth curves. For even n≥4, we determine the full automorphism group,of order (qn+1)q(q2−1), and give explicit equations and genera for all Galois quotients, with closed-form equations for several classes of subgroups.
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BibTeX
@misc{ma2026family,
title = {{A new family of maximal curves not covered by the Hermitian curve}},
author = {Liming Ma and Yipeng Wang},
howpublished = {arXiv},
year = {2026},
month = sep,
doi = {10.48550/arxiv.2609.19546},
eprint = {2609.19546},
archivePrefix = {arXiv},
url = {https://arxiv.org/abs/2609.19546},
note = {CC BY 4.0},
}
RIS
TY - UNPB
TI - A new family of maximal curves not covered by the Hermitian curve
AU - Liming Ma
AU - Yipeng Wang
PY - 2026
DA - 2026/09/17
PB - arXiv
DO - 10.48550/arxiv.2609.19546
UR - https://arxiv.org/abs/2609.19546
AB - For every prime power q and integer n≥1, we give a single Kummer equation defining an 𝔽_q^2n-maximal curve 𝒳_q,n. The family recovers the Hermitian curves for n=1,2, the Giulietti--Korchmáros curve for n=3, and the Beelen--Montanucci curves for odd n≥5. For q>2 and even n≥4, it gives new maximal curves of genus (q^2−1)q^n/2 that are not covered by the Hermitian curve over 𝔽_q^2n. We compute the genus for both parities of n and give a uniform proof of maximality by counting rational places. For q>2 and odd n≥5, we remove the Galois hypothesis from the known non-covering results for the Beelen--Montanucci and Garcia--Güneri--Stichtenoth curves. For even n≥4, we determine the full automorphism group,of order (q^n+1)q(q^2−1), and give explicit equations and genera for all Galois quotients, with closed-form equations for several classes of subgroups.
ER -