The Clebsch-Gordan Rule for 𝑈(𝔰𝔩₂), the Krawtchouk Algebras and the Hamming Graphs

Let 𝐷 ≥ 1 and 𝑞 ≥ 3 be two integers. Let 𝐻(𝐷) = 𝐻(𝐷, 𝑞) denote the 𝐷-dimensional Hamming graph over a q-element set. Let 𝒯(𝐷) denote the Terwilliger algebra of 𝐻(𝐷). Let 𝑉(𝐷) denote the standard 𝒯(𝐷)-module. Let ω denote a complex scalar. We consider a unital associative algebra 𝔎ω defined by genera...

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Veröffentlicht in:Symmetry, Integrability and Geometry: Methods and Applications
Datum:2023
1. Verfasser: Huang, Hau-Wen
Format: Artikel
Sprache:Englisch
Veröffentlicht: Інститут математики НАН України 2023
Online Zugang:https://nasplib.isofts.kiev.ua/handle/123456789/211867
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Назва журналу:Digital Library of Periodicals of National Academy of Sciences of Ukraine
Zitieren:The Clebsch-Gordan Rule for 𝑈(𝔰𝔩₂), the Krawtchouk Algebras and the Hamming Graphs. Hau-Wen Huang. SIGMA 19 (2023), 017, 19 pages

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Digital Library of Periodicals of National Academy of Sciences of Ukraine
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Zusammenfassung:Let 𝐷 ≥ 1 and 𝑞 ≥ 3 be two integers. Let 𝐻(𝐷) = 𝐻(𝐷, 𝑞) denote the 𝐷-dimensional Hamming graph over a q-element set. Let 𝒯(𝐷) denote the Terwilliger algebra of 𝐻(𝐷). Let 𝑉(𝐷) denote the standard 𝒯(𝐷)-module. Let ω denote a complex scalar. We consider a unital associative algebra 𝔎ω defined by generators and relations. The generators are 𝐴 and 𝐵. The relations are 𝐴²𝐵 − 2𝐴𝐵𝐴 + 𝐵𝐴² = 𝐵 + ω𝐴, 𝐵²𝐴 − 2𝐵𝐴𝐵 + 𝐴𝐵² = 𝐴 + ω𝐵. The algebra 𝔎ω is the case of the Askey-Wilson algebras corresponding to the Krawtchouk polynomials. The algebra 𝔎ω is isomorphic to U(𝔰𝔩₂) when ω² ≠ 1. We view 𝑉(𝐷) as a 𝔎₁₋₂/𝑞-module. We apply the Clebsch-Gordan rule for U(𝔰𝔩₂) to decompose 𝑉(𝐷) into a direct sum of irreducible 𝒯(𝐷)-modules.
ISSN:1815-0659