The pseudo-cosine sequences of a distance-regular graph
AA Pascasio, P Terwilliger - Linear algebra and its applications, 2006 - Elsevier
Linear algebra and its applications, 2006•Elsevier
Let Γ denote a distance-regular graph with diameter D⩾ 3, valency k, and intersection
numbers ai, bi, ci. By a pseudo-cosine sequence of Γ we mean a sequence of real numbers
σ0, σ1,…, σD such that σ0= 1 and ciσi− 1+ aiσi+ biσi+ 1= kσ1σi for 0⩽ i⩽ D− 1. Let σ0, σ1,…,
σD and ρ0, ρ1,…, ρD denote pseudo-cosine sequences of Γ. We say this pair of sequences
is tight whenever σ0ρ0, σ1ρ1,…, σDρD is a pseudo-cosine sequence of Γ. In this paper, we
determine all the tight pairs of pseudo-cosine sequences of Γ.
numbers ai, bi, ci. By a pseudo-cosine sequence of Γ we mean a sequence of real numbers
σ0, σ1,…, σD such that σ0= 1 and ciσi− 1+ aiσi+ biσi+ 1= kσ1σi for 0⩽ i⩽ D− 1. Let σ0, σ1,…,
σD and ρ0, ρ1,…, ρD denote pseudo-cosine sequences of Γ. We say this pair of sequences
is tight whenever σ0ρ0, σ1ρ1,…, σDρD is a pseudo-cosine sequence of Γ. In this paper, we
determine all the tight pairs of pseudo-cosine sequences of Γ.
Let Γ denote a distance-regular graph with diameter D⩾3, valency k, and intersection numbers ai, bi, ci. By a pseudo-cosine sequence of Γ we mean a sequence of real numbers σ0,σ1,…,σD such that σ0=1 and ciσi−1+aiσi+biσi+1=kσ1σi for 0⩽i⩽D−1. Let σ0,σ1,…,σD and ρ0,ρ1,…,ρD denote pseudo-cosine sequences of Γ. We say this pair of sequences is tight whenever σ0ρ0,σ1ρ1,…,σDρD is a pseudo-cosine sequence of Γ. In this paper, we determine all the tight pairs of pseudo-cosine sequences of Γ.
Elsevier
以上显示的是最相近的搜索结果。 查看全部搜索结果