PPT Slide

Dynamic Knowledge Assertion/Retraction

Prolog provides built in functions to work with Horn Clauses.

You can

1) Construct a structure representing a clause

2) add a clause to the database

3) remove a clause from the database

* All Prolog structures have the form functor ( arguments )

Facts are already in this form. To convert a rule to this form

P(X1, …, Xn) :- Q1(X1, …, Xn), Qa( ··), ···Qx( ···)

converts to

' :- ' (P(X1, .., Xn), ' , ' (Q1( ··), Qa( ···), ···Qk( ··) ) )

example: ' :- '( cat(X) , ', '( animal(X), furry(X) ) )