Group inverse and group involutory Matrices∗
Rafael Bru, Néstor Thome · Linear and Multilinear Algebra · 1998
In this work we deal with group involutory matrices, i.e.A #=A. We give necessary and sufficient conditions to characterize these matrices in terms of different representations of the group inverse. First, we give different expressions of the group inverse of a square matrix A. In addition, the special case of integer matrices is considered.