//
// Russell, R. and Norvig, P. (2010). Artificial intelligence: A modern
// approach, 3rd Edition. p. 348. Prentice Hall: Upper Saddle River, NJ.
//

// Jack owns a dog.
(exists x (and (dog x) (owns jack x)))

// Every dog owner is an animal lover.
(forall x (cond (exists y (and (dog y) (owns x y))) (animallover x)))

// No animal lover kills an animal
(forall x (cond (animallover x) (forall y (cond (animal y) (not (kills x y))))))

// Either Jack or Curiosity killed the cat, who is named Tuna
(or (kills jack tuna) (kills curiosity tuna))

// ...the cat, who is named Tuna
(cat tuna)

// All cats are animals (background information)
(forall x (cond (cat x) (animal x)))

// Prove that Curiosity killed Tuna
(kills curiosity tuna)