Regularity of quantum tau-functions generated by quantum birational Weyl group actions

We canonically quantize the tau-functions for the birational Weyl group action arising from a nilpotent Poisson algebra proposed by Noumi and Yamada. We also construct the q-difference deformation of the canonical quantization of the tau-functions. Using the translation functors for the symmetrizable Kac-Moody algebras, we prove the regularity of the quantum tau-functions, namely, we show that the quantum tau-functions are polynomials in dependent variables.