Journal of Lie Theory 17 (2007), No. 1, 145--161
Copyright Heldermann Verlag 2007
Infinite Fusion Products and sl2 Cosets
Evgeny Feigin
Independent University, Bolshoy Vlasievsky 11, 119002 Moscow, Russia
evgfeig@mccme.ru
[Abstract-pdf]
We study an approximation of tensor product of irreducible integrable $\widehat{{\frak{sl}}_2}$ representations by infinite fusion products. This gives an approximation of the corresponding coset theories. As an application we represent characters of spaces of these theories as limits of certain restricted Kostka polynomials. This leads to the bosonic (which is known) and fermionic (which is new) formulas for the $\widehat{{\frak{sl}}_2}$ branching functions.
Keywords: Cosets, branching functions, Kostka polynomials.
MSC: 17B67, 81R10
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