Prolog

• When I first moved to England (1997), the British AI people programmed in Prolog, while the American AI people programmed in Lisp.
• Now we all program in whatever is needed.
• Prolog is based on a subset of FOPL which is Turing Complete.
• You define rules (if then clauses), and give it a list of facts.
• This would mean in general, it is NP-complete, but you program by making rules that say how you derive new facts.
• The cut operator is really useful, and can make a prolog program much more efficient.
• The cut operator says give up, and stop looking for alternatives.
• This means that some proofs (and thus true facts) may not be derivable.
• It's really a different way to program.