8 papers
New Constructions of Distance-Biregular Graphs
Blas Fernández, Ferdinand Ihringer, Sabrina Lato +1
We construct a new family of distance-biregular graphs related to hyperovals and a new sporadic example of a distance-biregular graph related to Mathon's perp system. The infinite…
The Minimal Absolute Value of Sums of Fifth Roots of Unity
Akihiro Munemasa, Guillermo Núñez Ponasso
We determine the minimal absolute value of a non-vanishing sum of fifth roots of unity chosen with repetition, and characterize the corresponding sums. As a function of , th…
Sets of equiangular lines in dimension constructed from
Akihiro Munemasa, Ferenc SzöllÅsi, Kiyoto Yoshino
In 2023, Greaves, Syatriadi, and Yatsyna found a set of equiangular lines in , breaking the previous record. In 2025, Lin, Munemasa, Taniguchi, and Yoshino co…
Roux schemes which carry association schemes locally
Alexander L. Gavrilyuk, Jesse Lansdown, Akihiro Munemasa +1
A roux scheme is an association scheme formed from a special "roux" matrix and the regular permutation representation of an associated group. They were introduced by Iverson and Mi…
A 2-distance set with 277 points in the Euclidean space of dimension 23
Hong-Jun Ge, Jack Koolen, Akihiro Munemasa
We construct a -distance set with points in the -dimensional Euclidean space having distances and .
Antipodality of spherical designs with odd harmonic indices
Ryutaro Misawa, Akihiro Munemasa, Masanori Sawa
We determine the smallest size of a non-antipodal spherical design with harmonic indices to be , where is a positive integer. This is achieved by pro…