Almost-bipartite distance-regular graphs with the Q-polynomial property

Michael S. Lang, Paul M. Terwilliger
2007 European journal of combinatorics (Print)  
Let Γ denote a Q-polynomial distance-regular graph with diameter D ≥ 4. Assume that the intersection numbers of Γ satisfy a i = 0 for 0 ≤ i ≤ D − 1 and a D = 0. We show that Γ is a polygon, a folded cube, or an Odd graph.
doi:10.1016/j.ejc.2005.07.004 fatcat:mxm27cc6xbg5le53gutydzmkja