On the multiplicities of the primitive idempotents of a Q-polynomial distance-regular graph

Ito, Tanabe 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 Γ denote a distance-regular graph with diameter D ≥ 3. Suppose Γ is Q-polynomial with respect to the ordering E0, E1,...,...

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Main Author: Pascasio, Arlene A.
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Published: Animo Repository 2002
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Online Access:https://animorepository.dlsu.edu.ph/faculty_research/3606
https://animorepository.dlsu.edu.ph/context/faculty_research/article/4608/type/native/viewcontent/eujc.2002.0607
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spelling oai:animorepository.dlsu.edu.ph:faculty_research-46082021-09-17T08:20:57Z On the multiplicities of the primitive idempotents of a Q-polynomial distance-regular graph Pascasio, Arlene A. Ito, Tanabe 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 Γ denote a distance-regular graph with diameter D ≥ 3. Suppose Γ is Q-polynomial with respect to the ordering E0, E1,..., ED of the primitive idempotents. For 0 ≤ i ≤ D, let mi, denote the multiplicity of E i. Then (i) mi-1 ≤ mi (1 ≤ i ≤ D/2), (ii) mi ≤ mD-i (0 ≤ i ≤ D/2). By proving the above theorem we resolve a conjecture of Dennis Stanton. © 2002 Elsevier Science Ltd. All rights reserved. 2002-01-01T08:00:00Z text text/html https://animorepository.dlsu.edu.ph/faculty_research/3606 info:doi/10.1006/eujc.2002.0607 https://animorepository.dlsu.edu.ph/context/faculty_research/article/4608/type/native/viewcontent/eujc.2002.0607 Faculty Research Work Animo Repository Algebras, Linear Polynomials Algebra
institution De La Salle University
building De La Salle University Library
continent Asia
country Philippines
Philippines
content_provider De La Salle University Library
collection DLSU Institutional Repository
topic Algebras, Linear
Polynomials
Algebra
spellingShingle Algebras, Linear
Polynomials
Algebra
Pascasio, Arlene A.
On the multiplicities of the primitive idempotents of a Q-polynomial distance-regular graph
description Ito, Tanabe 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 Γ denote a distance-regular graph with diameter D ≥ 3. Suppose Γ is Q-polynomial with respect to the ordering E0, E1,..., ED of the primitive idempotents. For 0 ≤ i ≤ D, let mi, denote the multiplicity of E i. Then (i) mi-1 ≤ mi (1 ≤ i ≤ D/2), (ii) mi ≤ mD-i (0 ≤ i ≤ D/2). By proving the above theorem we resolve a conjecture of Dennis Stanton. © 2002 Elsevier Science Ltd. All rights reserved.
format text
author Pascasio, Arlene A.
author_facet Pascasio, Arlene A.
author_sort Pascasio, Arlene A.
title On the multiplicities of the primitive idempotents of a Q-polynomial distance-regular graph
title_short On the multiplicities of the primitive idempotents of a Q-polynomial distance-regular graph
title_full On the multiplicities of the primitive idempotents of a Q-polynomial distance-regular graph
title_fullStr On the multiplicities of the primitive idempotents of a Q-polynomial distance-regular graph
title_full_unstemmed On the multiplicities of the primitive idempotents of a Q-polynomial distance-regular graph
title_sort on the multiplicities of the primitive idempotents of a q-polynomial distance-regular graph
publisher Animo Repository
publishDate 2002
url https://animorepository.dlsu.edu.ph/faculty_research/3606
https://animorepository.dlsu.edu.ph/context/faculty_research/article/4608/type/native/viewcontent/eujc.2002.0607
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