|•||Rules are similar to queries|
|•||But they declare a conclusion in the head|
|•||In this way we can derive new facts from given facts|
|•||Rules are described by the vocabulary of the schema|
|•||But work on the facts that are given according to the schema|
Sample: what is the definition of an uncle?
„An uncle is the brother of one of my parents“
?A[hasUncle->?B] :- ?A:Person AND ?A
[hasParent->?P] AND ?P:Person AND ?P
[hasBrother->?B] AND ?B:Mann.