On graphs with smallest eigenvalue at least -3 and their lattices

On the Integrability of Strongly Regular Graphs

“…For the case of graphs with smallest eigenvalue at least −3, Koolen, Yang and Yang [24] generalized a result of Hoffman (1977) [21] and showed the following.…”

“…, 22} as their point sets, respectively. By following [13], we find that the Leech lattice Λ 24 is generated by the following 760 (= 1 + 759) vectors: 16 ), in which the positions of the eight 2's form a block of S (5,8,24).…”