  In this note I introduce a new approach to (or rather a new language for)
representation theory of groups. Namely, I propose to consider a (complex)
representation of a group $G$ as a sheaf on some geometric object (a stack).
  This point of view necessarily leads to a conclusion that the standard
approach to (continuous) representations of algebraic groups is ideologically
inconsistent. I propose a way to modify this approach using sheaves on stacks.
  In new version I corrected some misprints and added an explanation how
stack's approach is related to Vogan's picture of representations.
