let n be Nat; for K being Field holds
( 0. (K,n) is Idempotent & 0. (K,n) is Nilpotent )
let K be Field; ( 0. (K,n) is Idempotent & 0. (K,n) is Nilpotent )
( width (0. (K,n,n)) = n & len (0. (K,n,n)) = n )
by MATRIX_1:25;
then
(0. (K,n,n)) * (0. (K,n)) = 0. (K,n,n)
by MATRIX_6:1;
hence
( 0. (K,n) is Idempotent & 0. (K,n) is Nilpotent )
by Def1, Def2; verum