Measure is Monotone

Theorem
Let $$\left({X, \Sigma, \mu}\right)\ $$ be a measure space.

Then $$\mu$$ is monotone, that is:
 * $$\forall A, B \in \Sigma: A \subseteq B \implies \mu \left({A}\right) \le \mu \left({B}\right)$$

Proof
A direct corollary of Non-Negative Additive Function is Monotone.