Yufei Zhao: Equiangular lines and eigenvalue multiplicity #ICBS2024

Equiangular lines are configurations of lines in d-dimensional space, all passing through the origin, that pairwise make the same angle. I will discuss our solution to the following longstanding problem: fix an angle, in high dimensions, what is the maximum number of equiangular lines pairwise separated by the given angle? A key ingredient in the solution is a new theorem in spectral graph theory: the adjacency matrix of a connected bounded degree graph has sublinear second eigenvalue multiplicity. I will highlight some further research directions and open problems.

[nostalgichours]

from what i see this is the last yufei zhao vidoe on yt, thanks for the power of a point :D pdf