The Terwilliger Algebras of Bipartite Q-polynomial Distance-regular Graphs
摘要
Let Γ denote a bipartite Q-polynomial distance-regular graph with vertex set X, valency k ≥ 3 and diameter D ≥ 3. Let A be the adjacency matrix of Γ and let A*:= A*(x) be the dual adjacency matrix of Γ with respect to a fixed vertex x ∈ X. Let T:= T(x) denote the Terwilliger algebra of Γ generated by A and A*. In this paper, we first describe the relations between A and A*. Then we determine the dimensions of both T and the center of T, and moreover we give a basis of T.