Strange problem?! I'm confused(getting false instead of true)

[looloo1]

Hi,

This is my first assignment for Prolog:

I have to make sure that:

?- like(artos,oscar). is TRUE!


these are the statements:

(a) Artos is a dog.
(b) Dogs are fourlegged mammals.
(c) Dogs like little children.
(d) Oscar is a little child.

and these are my clauses:

dogs(artos).
fourleggedmammals(dogs).
like(dogs,littlechild).
littlechild(oscar).

I really don't understand why it says FALSE?

Does someone have an idea? I really appreciate it.

 

[joel76]

You have mistakes in your database.
You must assert your facts :

dogs(artos).
littlechild(oscar).

You have to give your rules :
"Dogs like little children" ==>

like(X, Y) :-
  dog(X),
  littlechild(Y).

Now it runs !

You have to translate "Dogs are fourlegged mammals.".