An Equivalence of Two Categories of sl(n,C)-Modules

We prove that the following two categories of sl(n,C)-modules are equivalent: (1) the category of modules with integral support filtered by submodules of Verma modules and complete with respect to Enright's completion functor; (2) the category of all subquotients of modules FM, where F is a finite-dimensional module and M is a fixed simple generic Gelfand–Zetlin module with integral central character. Our proof is based on an explicit construction of an equivalence which, additionally, commutes with translation functors. Finally, we describe some applications of this both to certain generalizations of the category O and to Gelfand–Zetlin modules.