2 problems

Let $G$ be a distance-regular graph with diameter $d$, with eigenvalues $\theta_0>\theta_1>\cdots>\theta_d$ and cosine sequences $(w_0(\theta_j),\ldots,w_d(\theta_j))$ correspondin…

Let $G$) be a distance-regular graph with diameter $d$, valency $k$, eigenvalues $\theta_0>\theta_1>ots>\theta_d$, and standard sequences $(w_0(\theta_j),...,w_d(\theta_j))$ corres…