Equiangular lines are lines in space that pass through a single point, and whose pairwise angles are all equal. Picture in 2D the three diagonals of a regular hexagon, and in 3D, the six lines connecting opposite vertices of a regular icosahedron (see the figure above). Mathematicians are not limited to three dimensions, however. “In high dimensions, things really get interesting, and the possibilities can seem limitless,” says Yufei Zhao, assistant professor of mathematics. But they aren’t limitless, according to Zhao and his team of MIT mathematicians, who sought to…
