Rule of Assumption/Boolean Interpretation

Definition
The truth value of a propositional formula $\mathbf A$ under a boolean interpretation $v$ is given by:


 * $\map v {\mathbf A} = \begin{cases}

\T & : \map v {\mathbf A} = \T \\ \F & : \map v {\mathbf A} = \F \end{cases}$