defpred S1[ Nat] means ( not n is empty implies n |^ n is even );
A1: for k being Nat st S1[k] holds
S1[k + 1]
proof
let k be Nat; :: thesis: ( S1[k] implies S1[k + 1] )
assume that
S1[k] and
not k + 1 is empty ; :: thesis: n |^ (k + 1) is even
n |^ (k + 1) = n * (n |^ k) by NEWTON:6;
hence n |^ (k + 1) is even ; :: thesis: verum
end;
A2: S1[ 0 ] ;
for k being Nat holds S1[k] from NAT_1:sch 2(A2, A1);
hence n |^ m is even ; :: thesis: verum