Re: where do I think wrong

>     half_or_full_siblings(X, Y) :-
>         (   same_father(X, Y),
> 	    X \== Y
> 	;   same_mother(X, Y),
> 	    \+ same_father(X, Y)
> 	).

 
Oke, I think this is what im searching for.
One rule for full and half siblings. 
 
But I do not understand why "is not equal"  is used.
As far as I understand this is what the rules says,
 
X and Y must have the same father.
X must not be the same as Y.
or X must have the same mother and must be not equal to X and Y have the same father.
 
What if the have the same father and not the same mother ?
 
Roelof
 
 		 	   		  
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