•The Identity Matrices

I _ 2 = (1 0) ; 0 1

I _ 3 = (1 0 0) ; 0 1 0 0 0 1

I _ 4 = (1 0 0 0) ; 0 1 0 0 0 0 1 0 0 0 0 1

Converted by Mathematica  (November 21, 2002)