Let α be a nonzero rational number α = ± p_1^(α_1) p_2^(α_2) ...p_L^(α_L), where p_1, ..., p_L are distinct primes, α_l element Z and α_l !=0. Then left bracketing bar a right bracketing bar product_(p prime) left bracketing bar α right bracketing bar _p | = | p_1^(α_1) p_2^(α_2) ...p_L^(α_L) p_1^(-α_1) p_2^(-α_2) ...p_L^(-α_L) | = | 1.