Keywords: Paley9-perfect.svg The Paley graph of order 9 colored with three colors and showing a clique of three vertices In this graph and each of its subgraphs the chromatic number equals the clique number so it is a perfect graph en wikipedia 2006-11-04 David Eppstein wikipedia en David Eppstein original upload log page en wikipedia Paley9-perfect svg 2006-11-04 21 46 David Eppstein 256×256×0 1992 bytes <nowiki>The Paley graph of order 9 colored with three colors and showing a clique of three vertices In this graph and each of its subgraphs the chromatic number equals the clique number so it is a perfect graph </nowiki> Files by User David Eppstein from en wikipedia Rook's graph 3x3 arrays Graphs with 9 vertices 4-regular graphs |