The Pseudo Cosine Sequences of a Distance-Regular Graph
| dc.creator | Pascasio, Arlene A. | |
| dc.creator | Terwilliger, Paul | |
| dc.date | 2003-12-08 | |
| dc.date.accessioned | 2026-07-07T05:03:38Z | |
| dc.date.available | 2026-07-07T05:03:38Z | |
| dc.description | Let $G$ denote a distance-regular graph with diameter $D\ge 3$, valency $k$, and intersection numbers $a_i$, $b_i$, $c_i$. By a {\it pseudo cosine sequence} of $G$ we mean a sequence of real numbers $s_0, s_1, ..., s_D$ such that $s_0=1$ and $c_i s_{i-1}+a_i s_i+b_i s_{i+1}=k s_1 s_i$ for $ 0 \le i \le D-1$. Let $s_0, s_1,..., s_D$ and $p_0, p_1, ..., p_D$ denote pseudo cosine sequences of $G$. We say this pair of sequences is {\it tight} whenever $s_0 p_0, s_1 p_1, ..., s_D p_D$ is a pseudo cosine sequence of $G$. In this paper, we determine all the tight pairs of pseudo cosine sequences of $G$. | |
| dc.description | 25 pages | |
| dc.identifier | https://arxiv.org/abs/math/0312150 | |
| dc.identifier | http://arxiv.org/abs/math/0312150 | |
| dc.identifier.uri | http://salesiana.dossiersoluciones.com/handle/123456789/69502 | |
| dc.subject | Combinatorics | |
| dc.subject | 05E50 | |
| dc.title | The Pseudo Cosine Sequences of a Distance-Regular Graph | |
| dc.type | text |