Open AccessSome properties of the Hoffman-Singleton graph
Author(s) -
Peter Rowlinson,
Irene Sciriha
Publication year - 2007
Publication title -
applicable analysis and discrete mathematics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.69
H-Index - 26
eISSN - 2406-100X
pISSN - 1452-8630
DOI - 10.2298/aadm0702438r
Subject(s) - mathematics , singleton , combinatorics , graph , discrete mathematics , pregnancy , genetics , biology
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.
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