Can Kozcaz

We introduce the R-matrix formulation of qq-characters and corresponding Frenkel-Reshetikhin deformed W-algebras. The R-matrix featuring in the construction is of the Ding-Iohara-Miki (DIM) algebra, while the type of the qq-character is determined by the network of Fock representations corresponding to a web of 5-branes geometrically engineering a quiver gauge theory. This formulation gives in a unified fashion the expressions for the characters of A_n and \hat{A}_n types. In the latter case we discover new qq-characters, which are Laurent series in the instanton parameter.