The t-analog of the level one string function for twisted affine Kac–Moody algebras

The trascendence of Kac-Moody algebras

“…He also gives an example to show that the Poincare series of the principal nilpotent filtration is not always equal to the q-analog of weight multiplicity, and finally, he we gives some partial results for indefinite Kac-Moody algebras. S.S. Sharma and S. Viswanath have studied in [234,235] Lusztig's t-analog of weight multiplicities associated to level one representations of twisted affine Kac-Moody algebras. They obtained an explicit closed form expression for the corresponding t-string function using constant term identities of Macdonald and Cherednik.…”