). lectures(turing, 9020). is also called a predicate Facts about a hypothetical computer science department: % lectures(X, Y): person X lectures in course Y lectures( turing , 9020). lectures( codd , 9311). lectures( backus , 9021). lectures( ritchie , 9201). lectures( minsky , 9414). lectures(codd, 9314). % studies(X, Y): person X