### Abstract

When can one see from the spectrum of a graph whether it is distance-regular or not?We give some new results for when this is the case.As a consequence we find (among others) that the following distance-regular graphs are uniquely determined by their spectrum: The collinearity graphs of the generalized octagons of order (2; 1), (3; 1) and (4; 1), the Biggs-Smith graph, the M22 graph, and the coset graphs of the doubly truncated binary Golay code and the extended ternary Golay code.

Original language | English |
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Place of Publication | Tilburg |

Publisher | Operations research |

Number of pages | 12 |

Volume | 793 |

Publication status | Published - 2000 |

### Publication series

Name | FEW Research Memorandum |
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Volume | 793 |

### Keywords

- graph theory
- graphs

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## Cite this

van Dam, E. R., & Haemers, W. H. (2000).

*Spectral Characterizations of Some Distance-Regular Graphs*. (FEW Research Memorandum; Vol. 793). Operations research.