\begin{definition}[Definition:Conditional Probability]
Let $\EE$ be an experiment with probability space $\struct {\Omega, \Sigma, \Pr}$.
Let $A, B \in \Sigma$ be events of $\EE$.
We write the '''conditional probability of $A$ given $B$''' as $\condprob A B$, and define it as:
:''the probability that $A$ has occurred, given that $B$ has occurred.''
\end{definition}