Zeros and poles of quantum current operators and the condition of quantum integrability

For the current realization of the affine quantum groups, a simple comultiplication for the quantum current operators was given by Drinfeld. With this comultiplication, we study the zeros and poles of the quantum current operators and present a condition of integrability on the quantum current of $U_q\left(\hat{\frak sl}(2)\right)$, which is a deformation of the corresponding condition for $\hat{\frak sl}(2)$. We also present the results about the zeros and poles of the quantum current operators of $U_q\left(\hat{\frak sl}(n)\right)$.