On the Grothendieck group of modules supported in a nilpotent orbit in the Lie algebra gl(n)

The Grothendieck groups of equivariant modules supported in conjugacy classes of nilpotent matrices are investigated. The generators given by twisted modules corresponding to dominant weights in the case of the set of nilpotent matrices are given. Finally the formulas relating the characters of twisted modules for different conjugacy classes are given by means of degeneration sequences.