## Incidence graph of $(13,9,3)$-design

The incidence graph of the complementary design of $PG(2,3)$ (and the distance-3 graph of its incidence graph).

Number of vertices: | $26$ |

Diameter: | $3$ |

Intersection array: | $\{9,8,3;1,6,9\}$ |

Spectrum: | $9^1 (\sqrt{3})^{12} (-\sqrt{3})^{12} (-9)^1$ |

Automorphism group: | $Aut(PSL(3,3)) \cong PSL(3,3):2$ |

Distance-transitive: | Yes |

Bipartite |