Expert System - Mr. Rigby family tree expert system

expert-system.pl

/* Our knowledge base */
parent(jeff, jared).
parent(jeff, adam).
parent(diane, jared).
parent(diane, adam).
parent(george, diane).
parent(doris, diane).
parent(gerald, jeff).
parent(june, jeff).
parent(gerald, jill).
parent(june, jill).
parent(jill, aaron).
parent(jill, ireyna).
parent(jill, jason).
parent(paul, aaron).
parent(paul, ireyna).
parent(paul, jason).
parent(adam, jessica).
parent(frankie, jessica).

/* Our rules base */
grandparent(G, C) :-
    parent(G, P),
    parent(P, C).

sibling(A, B) :-
    parent(P, A),
    parent(P, B),
    not(A=B).

cousin(A, B) :-
    grandparent(G, A),
    grandparent(G, B),
    not(sibling(A, B)),
    not(A=B).