An interpretation or structure in predicate logic is a tuple \(\mathcal{A} = (U, \phi, \varphi, \xi)\) where:
- \(U\) is a non-empty universe
- \(\phi\) assigns function symbols to functions \(U^k \rightarrow U\)
- {{c3::\(\varphi\) assigns predicate symbols to functions \(U^k \rightarrow \{0,1\}\)}}
- \(\xi\) assigns variable symbols to values in \(U\)
- \(U\) is a non-empty universe
- \(\phi\) assigns function symbols to functions \(U^k \rightarrow U\)
- {{c3::\(\varphi\) assigns predicate symbols to functions \(U^k \rightarrow \{0,1\}\)}}
- \(\xi\) assigns variable symbols to values in \(U\)