I've got a rule in my Prolog program called blanket(X,Y) which checks if X is in a certain kind of set of Y which consists of:
I've defined it as follows :
blanket(Y,X) :- different(Y,X),parent(Y,X);child(Y,X);coparent(Y,X).
However, this doesn't work as I expect. It correctly identifies X's parents, children, and coparents (if any) but it lists itself as both a parent and a coparent, which I do not want. Is it possible to set some kind of order, so that the different(Y,X) evaluates first and independently? I tried something like : different(Y,X),(parent(Y,X);child(Y,X);coparent(Y,X))., of course, but that yields a syntax error as I"m still quite unfamiliar with the language.
Any suggestions would be greatly appreciated.
EDIT: Here are the child, different, and coparent relations:
child(X,Y) :- parent(Y,X).
different(X,Y) :- not(X == Y).
coparent(Y,X) :- parent(Y,Z),parent(X,Z).
For completeness.
blanket(Y,X) :- different(Y,X), parent(Y,X).
blanket(Y,X) :- different(Y,X), child(Y,X).
blanket(Y,X) :- different(Y,X), coparent(Y,X).