Extended T-systems
  We use the theory of q-characters to establish a number of short exact sequences in the category of finite-dimensional representations of the quantum affine groups of types A and B. That allows us to introduce a set of 3-term recurrence relations which contains the celebrated T-system as a special case. 
E. Mukhin and C. A. S. Young
math.QA hep-th math-ph math.MP