Partial Gauss decomposition, \bf $U_q(\widehat{{{\frak{gl}}}(n-1)})\in   U_q(\widehat{{{\frak{gl}}}(n)}) $ and Zamolodchikov algebra
  We use the idea of partial Gauss decomposition to study structures related to $U_q(\widehat{{{\frak{gl}}}(n-1)})$ inside $U_q(\widehat{{{\frak{gl}}}(n)}) $. This gives a description of $U_q(\widehat{{{\frak{gl}}}(n)})$ as an extension of $U_q(\widehat{{{\frak{gl}}}(n-1)})$ with Zamolodchikov algebras, We explain the connection of this new realization with form factors. 
Jintai Ding