Fuente TeX:

\varphi \not\in \Gamma \text{ y } \Gamma \text{ CM } \Rightarrow \lnot\varphi \in \Gamma \text{ [} \Gamma \text{ CM sii } (\bar{\forall}\varphi \in PROP)(\varphi \in \Gamma \text{ o } \lnot \varphi \in \Gamma) \text{]}