Sorry for the maybe stupid question, but I'm struggling with a problem concerning constraints in datalog. I basically have to color 2 objects with 2 different colors. The problem is that the constraint that I have to define for "2 objects can't have the same color" leads me to an empty model. I don't understand why. Any help?
Here is the code:
Object(a). Object(b).
Colored(X,red) v Colored(X,blue) :- Object(X).
:- Colored(X, C), Colored(Y, C).
