On bipartite Q-polynomial distance-regular graphs with c2=1

Štefko Miklavič
2007 Discrete Mathematics  
Let denote a bipartite Q-polynomial distance-regular graph with diameter d 3, valency k 3 and intersection number c 2 = 1. We show that has a certain equitable partition of its vertex set which involves 4d − 4 cells. We use this partition to show that the intersection numbers of satisfy the following divisibility conditions: Using these divisibility conditions we show does not exist if d = 4.
doi:10.1016/j.disc.2005.09.044 fatcat:vephvt5isrh4hpt27ngogaor24