example.datalog

adviser(
   "Andrew Rice",
   "Mistral Contrastin"
   )

   .
adviser("Andy Hopper",                          "Andrew Rice").
adviser("Alan Mycroft", "Dominic Orchard").
adviser("David Wheeler", "Andy Hopper").
adviser("Rod Burstall", "Alan Mycroft").
adviser("Robin Milner", "Alan Mycroft").
academicAncestor(X, Y) :-



  adviser(X, Y).


academicAncestor(X, Z) :-
  adviser(X, Y),
  academicAncestor(Y, Z).