Enregistré dans:
Détails bibliographiques
Auteurs principaux: Lin, Yen-chi Roger, Munemasa, Akihiro, Taniguchi, Tetsuji, Yoshino, Kiyoto
Format: Preprint
Publié: 2025
Sujets:
Accès en ligne:https://arxiv.org/abs/2503.06377
Tags: Ajouter un tag
Pas de tags, Soyez le premier à ajouter un tag!
_version_ 1866913914604748800
author Lin, Yen-chi Roger
Munemasa, Akihiro
Taniguchi, Tetsuji
Yoshino, Kiyoto
author_facet Lin, Yen-chi Roger
Munemasa, Akihiro
Taniguchi, Tetsuji
Yoshino, Kiyoto
contents In 2023, Greaves et~al.\ constructed several sets of 57 equiangular lines in dimension 18. Using the concept of switching root introduced by Cao et~al.\ in 2021, these sets of equiangular lines are embedded in a lattice of rank 19 spanned by norm 3 vectors together with a switching root. We characterize this lattice as an overlattice of the root lattice $A_9\oplus A_9\oplus A_1$, and show that there are at least $246896$ sets of 57 equiangular lines in dimension $18$ arising in this way, up to isometry. Additionally, we prove that all of these sets of equiangular lines are strongly maximal. Here, a set of equiangular lines is said to be strongly maximal if there is no set of equiangular lines properly containing it even if the dimension of the underlying space is increased. Among these sets, there are ones with only six distinct Seidel eigenvalues.
format Preprint
id arxiv_https___arxiv_org_abs_2503_06377
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Sets of equiangular lines in dimension $18$ constructed from $A_9 \oplus A_9 \oplus A_1$
Lin, Yen-chi Roger
Munemasa, Akihiro
Taniguchi, Tetsuji
Yoshino, Kiyoto
Combinatorics
05B40, 05B20, 05C50, 05C70
In 2023, Greaves et~al.\ constructed several sets of 57 equiangular lines in dimension 18. Using the concept of switching root introduced by Cao et~al.\ in 2021, these sets of equiangular lines are embedded in a lattice of rank 19 spanned by norm 3 vectors together with a switching root. We characterize this lattice as an overlattice of the root lattice $A_9\oplus A_9\oplus A_1$, and show that there are at least $246896$ sets of 57 equiangular lines in dimension $18$ arising in this way, up to isometry. Additionally, we prove that all of these sets of equiangular lines are strongly maximal. Here, a set of equiangular lines is said to be strongly maximal if there is no set of equiangular lines properly containing it even if the dimension of the underlying space is increased. Among these sets, there are ones with only six distinct Seidel eigenvalues.
title Sets of equiangular lines in dimension $18$ constructed from $A_9 \oplus A_9 \oplus A_1$
topic Combinatorics
05B40, 05B20, 05C50, 05C70
url https://arxiv.org/abs/2503.06377