Solution: Model theory basics
\(\mathcal{M} = \langle D, I\rangle\) with domain:
\[\begin{align*} D = \{a,b,c,d,e\} \end{align*}\]Interpretation function:
\[\begin{align*} I(\con{anna}) &= a\\ I(\con{ben}) &= b\\ I(\con{cara}) &= c\\ I(\con{student}) &= \{a,b\}\\ I(\con{linguist}) &= \{b,c\}\\ I(\con{book}) &= \{d,e\}\\ I(\con{admire}) &= \{(a,b),(b,c),(c,d)\}\\ I(\con{read}) &= \{(a,d),(b,e),(c,d),(a,e)\}\\ I(\con{recommend}) &= \{(a,d),(c,a),(c,d)\}\\ \end{align*}\]Environment:
\[\begin{align*} g=\lbrace (x,a), (y,b)\rbrace \end{align*}\]- \[\begin{gather*} \con{student}\con{anna}\quad\checkmark \\ \con{book}\con{anna}\quad\times\\ \con{linguist}\con{cara}\quad\checkmark\\ \con{admire}\con{ben}\con{anna}\quad\checkmark\\ \con{admire}\con{anna}\con{ben}\quad\times\\ \end{gather*}\]
- \[\begin{gather*} \interp{\exists x.\con{student}x} = 1\\ \interp{\forall x.\con{student}x \rightarrow \con{linguist}x} = 0\\ \interp{\exists x.\con{student}x \land \con{linguist}x} = 1\\ \interp{\forall x.\con{book}x \rightarrow \con{student}x} = 0\\ \interp{\exists x\forall y. \con{admire}y\cnct x} = 0\\ \interp{\con{student}x} = 1\\ \interp{\con{linguist}x} = 0\\ \interp{\exists x.\con{admire}x\cnct y} = 1 \\ \end{gather*}\]
- Translate the following sentences into FOL:
- Anna is a student.
- Ben read a book.
- Every student read a book.
- Some linguist recommended every book.
or, possibly,
\[\forall x. book'x \to \exists y.linguist'y \land recom'x\cnct y\]- No student recommended Ben.
- Not every student read a book.
- No book is read by every student.
- Some book is read by every student.
- Translate the following sentences into FOL; you are not allowed to use a
cardinality predicate:
- Exactly one student laughed.
- At least two students laughed.
- No more than one student laughed.