TY - JOUR TI - Some properties of the Hoffman-Singleton graph AU - Rowlinson Peter AU - Sciriha Irene JN - Applicable Analysis and Discrete Mathematics PY - 2007 VL - 1 IS - 2 SP - 438 EP - 445 PT- Article AB- The Hoffman-Singleton graph, with spectrum 7(1), 2(28), -3(21), is characterized among regular graphs by a star complement for the eigenvalue 2 that is, by an induced subgraph of order 22 without 2 as an eigenvalue. Properties of other induced subgraphs are noted; in particular, the subgraph induced by vertices at distance 2 from a given vertex is the edge-disjoint union of three Hamiltonian cycles.