Definition
Let and be propositional formulas, then,
\operatorname{Sub}(\varphi(p_{0},p_{1},\ldots,p_{n})) $$ is the formula obtained by simultaneously substituting each $\alpha_{i}$ in for $p_{i}$. #### ExamplesLet φ(p0,p1,…,pn) and α0,α1,…,αn be propositional formulas, then,
\operatorname{Sub}(\varphi(p_{0},p_{1},\ldots,p_{n})) $$ is the formula obtained by simultaneously substituting each $\alpha_{i}$ in for $p_{i}$. #### Examples