Event Space contains Sample Space

Theorem
Let $\mathcal E$ be an experiment with a probability space $\left({\Omega, \Sigma, \Pr}\right)$.

The event space $\Sigma$ of $\mathcal E$ has the property that:
 * $\Omega \in \Sigma$

where $\Omega$ is the sample space of $\mathcal E$.

Also see

 * Elementary Properties of Event Space