asp_wikipedia_example2.pl

#domain person(P).

citizen(P) :- born_in_usa(P).
citizen(P) :- not_born_in_usa(P), resident_usa(P), naturalized(P).
citizen(P) :- not_born_in_usa(P), mother(Y,P), citizen(Y), registered(P).

#hide mother(P, Y).
mother(mary, john).

#hide citizen(P).
citizen(mary).

#hide person(P).
person(john).

:- resident_usa(john).
:- born_in_usa(P), not_born_in_usa(P).
:- born_in_usa(P), registered(P).
:- born_in_usa(P), naturalized(P).
:- born_in_usa(P), resident_usa(P).
:- registered(P), naturalized(P).

{born_in_usa(P)}.
{resident_usa(P)}.
{naturalized(P)}.
{not_born_in_usa(P)}.
{registered(P)}.

compute { citizen(john) }.