https://maximummathematics.com/books/foundational-mathematics/logic/multiple-quantifiers/index.htmlIn an earlier section, we examined propositional functions with two and three variables. For each variable in an open statement, we needed to substitute some value from the respective universe in order to determine the statement’s truth value. Here, we look at quantifying statements with two or more variables. Bound and Free Variables BOUND VARIABLE, FREE VARIABLE For some universe $\mathcal{U}$, consider a propositional function $p(x, y)$ where $x$ and $y$ are both constrained by $\mathcal{U}$, and the quantified statementsHugoen-US