Fuente TeX:

\begin{array}{l l}\mathcal{M}  \models P(\bar{a}) & \text{por lo que:}\\\exists b \in   \vert \mathcal{M} \vert . \mathcal{M}  \models (P(\bar{a}) & (\text{En particular, el } a \text{ que estamos considerando}) \\\mathcal{M} \models (\exists z )(P(z)) & (\text{ por 2.4.5 para } \exists )\end{array}