The extended $T$-systems are a number of short exact sequences in the category of finite-dimensional modules over the quantum affine algebras of types $A_n^{ (1)}$ and $B_n^{ (1)}$, introduced by Mukhin and Young as a generalization of the $T$-systems. In this paper we establish the extended $T$-systems for more general modules, which are constructed from an arbitrary strong duality datum of type $A$. Our approach does not use the theory of $q$-characters, and so also provides a new proof to the original Mukhin-Young's extended $T$-systems.
Categories: math.QA math.RT