Divisor Sum of Non-Square Semiprime/Proof 1

Proof
As $p$ and $q$ are distinct prime numbers, it follows that $p$ and $q$ are coprime.

Thus by Sigma Function is Multiplicative:
 * $\map \sigma n = \map \sigma p \map \sigma q$

From Sigma Function of Prime Number:
 * $\map \sigma p = \paren {p + 1}$
 * $\map \sigma q = \paren {q + 1}$

Hence the result.