3 papers
math.CO2024
Equiangular lines and eigenvalue multiplicities
Yufei Zhao
Expository article on the problem of determining the maximum number of equiangular lines with a fixed angle, and the associated problem of second eigenvalue multiplicity in graphs.
math.PR2024
Spectral non-concentration near the top for unimodular random graphs
Mikolaj Fraczyk, Ben Hayes, Madhu Sudan +1
In recent work on equiangular lines, Jiang, Tidor, Yuan, Zhang, and Zhao showed that a connected bounded degree graph has sublinear second eigenvalue multiplicity. More generally t…
math.CO2023
Uniacute Spherical Codes
Saba Lepsveridze, Aleksandre Saatashvili, Yufei Zhao
A spherical -code, where , consists of unit vectors in whose pairwise inner products are contained in . Determining the maximum cardin…