Decompositions of matrices into a sum of invertible matrices and matrices of fixed nilpotence.

Abstract

For any n ≥ 2 and fixed k ≥ 1, we give necessary and sufficient conditions for an arbitrary nonzero square matrix in the matrix ring Mn(F) to be written as a sum of an invertible matrix U and a nilpotent matrix N with Nk = 0 over an arbitrary field F.