Prologで相対ルールを定義する方法は?
これは私がこれまでに得たものです:
spouce(X,Y) :-
wife(X,Y).
spouce(X,Y) :-
husband(X,Y).
relative-by-blood(X,Y) :-
ancestor(Z,X),
ancestor(Z,Y).
relative(X,Y) :-
relative-by-blood(X,Y).
relative(X,Y) :-
spouce(X,Y).
relative(X,Y) :-
relative-by-blood(X,Z), %<- not sure what to do here.
前もって感謝します!