rother}(y,x) {\;\;{\Leftrightarrow}\;\;}{Loves}(x,y)] {\:\;{\Rightarrow}\:\;}{Happy}(x)$.<br />

3.  No dog bites a child of its owner.<br />

    1.  ${\forall\,x\;\;} {Dog}(x) {\:\;{\Rightarrow}\:\;}\lnot {Bites}(x,{Child}({Owner}(x)))$.<br />

    2.  $\lnot {\exists\,x,y\;\;} {Dog}(x) \land {Child}(y,{Owner}(x)) \land {Bites}(x,y)$.<br />

    3.  ${\forall\,x\;\;} {Dog}(x) {\:\;{\Rightarrow}\:\;}({\forall\,y\;\;} {Child}(y,{Owner}(x)) {\:\;{\Rightarrow}\:\;}\lnot {Bites}(x,y))$.<br />

    4.  $\lnot {