let a, b, m be Nat; :: thesis: a + b divides (a |^ ((2 * m) + 1)) + (b |^ ((2 * m) + 1))
A2: (a |^ ((2 * m) + 2)) - (b |^ ((2 * m) + 2)) = (((a |^ ((2 * m) + 1)) + (b |^ ((2 * m) + 1))) * (a - b)) + ((a * b) * ((a |^ (2 * m)) - (b |^ (2 * m)))) by Th21;
set n = m + 1;
consider t being Integer such that
A4: (a |^ (2 * m)) - (b |^ (2 * m)) = ((a |^ 2) - (b |^ 2)) * t by Th33, INT_1:def 3;
consider z being Integer such that
A4a: (a |^ (2 * (m + 1))) - (b |^ (2 * (m + 1))) = ((a |^ 2) - (b |^ 2)) * z by Th33, INT_1:def 3;
A5: (a - b) * ((a |^ ((2 * m) + 1)) + (b |^ ((2 * m) + 1))) = ((a |^ ((2 * m) + 2)) - (b |^ ((2 * m) + 2))) - ((a * b) * ((a |^ (2 * m)) - (b |^ (2 * m)))) by A2
.= ((a |^ (2 * (m + 1))) - (b |^ (2 * (m + 1)))) - ((a * b) * (((a |^ 2) - (b |^ 2)) * t)) by A4
.= ((a |^ 2) - (b |^ 2)) * (z - ((a * b) * t)) by A4a
.= ((a - b) * (a + b)) * (z - ((a * b) * t)) by Th1
.= (a - b) * ((a + b) * (z - ((a * b) * t))) ;
X: 2 * a = a + a ;
( (a |^ ((2 * m) + 1)) + (b |^ ((2 * m) + 1)) = (a + b) * (z - ((a * b) * t)) or a - b = 0 ) by A5, XCMPLX_1:5;
hence a + b divides (a |^ ((2 * m) + 1)) + (b |^ ((2 * m) + 1)) by Lm46, X; :: thesis: verum