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This article is cited in 4 scientific papers (total in 5 papers)
String Functions for Affine Lie Algebras Integrable Modules
Petr Kulisha, Vladimir Lyakhovskyb a Sankt-Petersburg Department of Steklov Institute of Mathematics, Fontanka 27, 191023, Sankt-Petersburg, Russia
b Department of Theoretical Physics, Sankt-Petersburg State University, 1 Ulyanovskaya Str., Petergof, 198904, Sankt-Petersburg, Russia
Abstract:
The recursion relations of branching coefficients $k_{\xi}^{(\mu)}$ for a module $L_{\mathfrak g\downarrow\mathfrak h}^\mu$ reduced to a Cartan subalgebra $\mathfrak h$ are transformed in order to place the recursion shifts $\gamma\in\Gamma _{\mathfrak a\subset\mathfrak h}$ into the fundamental Weyl chamber. The new ensembles $F\Psi$ (the “folded fans”) of shifts were constructed and the corresponding
recursion properties for the weights belonging to the fundamental Weyl chamber were formulated. Being considered simultaneously for the set of string functions (corresponding to the same congruence class $\Xi_{v}$ of modules) the system of recursion relations constitute an equation
$\mathbf M_{(u)}^{\Xi _v}\mathbf{m}_{(u)}^{\mu}={\boldsymbol\delta}_{(u)}^{\mu}$ where the operator $\mathbf M_{(u)}^{\Xi _v}$ is an invertible matrix whose elements are defined by the coordinates and multiplicities of the shift weights in the folded fans $F\Psi$ and the components of the vector
$\mathbf m_{(u)}^\mu$ are the string function coefficients for $L^\mu$ enlisted up to an arbitrary fixed grade $u$. The examples are presented where the string functions for modules of $\mathfrak g=A_2^{(1)}$ are explicitly constructed demonstrating that the set of folded fans provides a compact and effective tool to study the integrable highest weight modules.
Keywords:
affine Lie algebras; integrable modules; string functions.
Received: September 15, 2008; in final form December 4, 2008; Published online December 12, 2008
Citation:
Petr Kulish, Vladimir Lyakhovsky, “String Functions for Affine Lie Algebras Integrable Modules”, SIGMA, 4 (2008), 085, 18 pp.
Linking options:
https://www.mathnet.ru/eng/sigma338 https://www.mathnet.ru/eng/sigma/v4/p85
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