The Terwilliger Algebra of a 2-Homogeneous Bipartite Distance-Regular Graph
โ Scribed by Brian Curtin
- Publisher
- Elsevier Science
- Year
- 2001
- Tongue
- English
- Weight
- 200 KB
- Volume
- 81
- Category
- Article
- ISSN
- 0095-8956
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โฆ Synopsis
Let 1 denote a 2-homogeneous bipartite distance-regular graph with diameter D 3 and valency k 3. Assume that 1 is not isomorphic to a Hamming cube. Fix a vertex x of 1, and let T=T(x) denote the Terwilliger algebra of T with respect to x. We give three sets of generators for T, two of which satisfy the relations of the quantum universal enveloping algebra of the Lie algebra sl(2). We then describe the simple T-modules. We give a pair of canonical bases for each simple T-module, and we give the overlap function for these bases in terms of a basic hypergeometric function. Finally, we give two generators for the center of T.
๐ SIMILAR VOLUMES
In this paper, we consider a bipartite distance-regular graph = (X, E) with diameter d โฅ 3. We investigate the local structure of , focusing on those vertices with distance at most 2 from a given vertex x. To do this, we consider a subalgebra R = R(x) of Mat X (C), where X denotes the set of vertice
and Terwilliger recently introduced the notion of a tridiagonal pair. We apply their results to distance-regular graphs and obtain the following theorem. THEOREM. Let denote a distance-regular graph with diameter D โฅ 3. Suppose is Q-polynomial with respect to the ordering E 0 , E 1 , . . . , E D of