\begin{definition}[Definition:Boolean Interpretation/Formal Semantics/Invalid]
Let $\phi$ be a WFF of propositional logic.
$\phi$ is declared '''($\mathrm{BI}$-)invalid''' in a boolean interpretation $v$ {{iff}}:
:$\map v \phi = \F$
Symbolically, this can be expressed as:
:$v \not\models_{\mathrm{BI}} \phi$
Category:Definitions/Boolean Interpretations
\end{definition}