First-order logic
- \[\begin{gather*} \con{student}\con{anna}\\ \con{book}\con{anna}\\ \con{linguist}\con{cara}\\ \con{admire}\con{ben}\con{anna}\\ \con{admire}\con{anna}\con{ben}\\ \end{gather*}\]
- \[\begin{gather*} \exists x.\con{student}x\\ \forall x.\con{student}x \rightarrow \con{linguist}x\\ \exists x.\con{student}x \land \con{linguist}x\\ \forall x.\con{book}x \rightarrow \con{student}x\\ \exists x\forall y. \con{admire}y\cnct x\\ \con{student}x\\ \con{linguist}x\\ \exists x.\con{admire}x\cnct y\\ \end{gather*}\]
- Translate the following sentences into FOL, and evaluate in :
- Anna is a student.
- Ben read a book.
- Every student read a book.
- Some linguist recommended every book.
- No student recommended Ben.
- Not every student read a book.
- No book is read by every student.
- Some book is read by every student.
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You have two predicates \(p\) and \(q\). Express the following situations in first order logic:
- there is no \(p\) that is not also \(q\).
- there is exactly one \(p\).
- there are exactly two \(p\)s.
- there is at most one \(p\).
For each pair, determine the logical relation between the left and right formulas (implies, contradicts, or independent):
\[\begin{gather} \forall x.\con{p}x\rightarrow \con{q}x& \exists x.\con{p}x\\ \forall x.\con{p}x\rightarrow \con{q}x& \exists x.\con{q}x\\ \exists x.\con{p}x\wedge \con{q}x& \exists x.\con{p}x\\ \forall x.\con{p}x &\exists x.\con{p}x\\ \neg\exists x\,\con{r}x& \forall x.\neg\con{r}x\\ \forall x.\con{p}x\land\con{r}x& \forall x.\con{p}x\rightarrow \con{r}x\\ \forall x.\con{p}x\land\con{r}x& \forall x.\con{p}x :\land. \forall x.\con{r}x\\ \forall x.\con{p}x\lor\con{r}x& \forall x.\con{p}x :\lor. \forall x.\con{r}x\\ \exists x.\con{p}x\land\con{r}x& \exists x.\con{p}x :\land. \exists x.\con{r}x\\ \exists x.\con{p}x\lor\con{r}x& \exists x.\con{p}x :\lor. \exists x.\con{r}x\\ \end{gather}\] 🗝️Translate to first-order logic:
- No one speaks French. (Note: you can take \emph{speak French} as a single lexical item. But, if you like, try to take the two words separately.)
- No one speaks French or Arabic.
- Every student is happy.
- Every student is happy and tired.
- Every student is happy, and every student is tired.
- Every student is happy or tired.
- Every student is happy, or every student is tired.