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