Affine Pieri rule for periodic Macdonald spherical functions and fusion rings

Jan Felipe van Diejen, Erdal Emsiz, Ignacio N. Zurrián

Let $\hat{\mathfrak{g}}$ be an untwisted affine Lie algebra or the twisted counterpart thereof (which excludes the affine Lie algebras of type ${\widehat{BC}}_n=A_{2n}^{(2)}$). We pr…