Like other Kac–Moody algebras, affine Lie algebras satisfy the Weyl–Kac character formula, which expresses the characters of the algebra in terms of their highest weights. In the case of affine Lie algebras, the resulting identities are equivalent to the Macdonald identities. In particular, for the affine Lie algebra of type A 1 ( 1 ) , associated to the affine symmetric group S ~ ~ 2 , the corresponding Macdonald identity is equivalent to the Jacobi triple product.