Let $P = (\Omega, \mathcal{F}, \mathbb{P})$ be a D1159: Probability space such that

(i) | $E, F \in \mathcal{F}$ are each an D1716: Event in $P$ |

Then
\begin{equation}
\mathbb{P} \left( E \cup F \right)
\leq \mathbb{P}(E) + \mathbb{P}(F)
\end{equation}