CycL

;;; Simple CycL example demonstrating knowledge representation

;;; Define that Socrates is a person
(isa Socrates Person)

;;; Define that all persons are mortal
(implies
  (isa ?X Person)
  (isa ?X MortalBeing))

;;; Define that Socrates is born in Athens
(birthPlace Socrates Athens)

;;; Define that Athens is a city
(isa Athens City)

;;; Query to prove Socrates is mortal
(and
  (isa Socrates Person)
  (isa Socrates MortalBeing))