On the category of modules of second kind for Galois coverings

摘要

Let F : R:R/G be a Galois covering and modi(R/G) (resp. mod.2(R/G)) be a full subcategory of the module category mod(R/G), consisting of all i^/C-modules of first (resp. second) kind with respect to F. The structure of the categories (mod(R/G))/ [modi(R/G)] and mod.2(R/G) is given in terms of representation categories of stabilizers of weakly-G-periodic modules for some class of coverings.