/* family2.pl
 *
 * Another family example for CS 313
 */

l :- [family2].

motherOf(amy, anna).
motherOf(amy, peter).
motherOf(lorle, daniel).
motherOf(lorle, felix).
motherOf(oma, lorle).

fatherOf(daniel, anna).
fatherOf(daniel, peter).
fatherOf(felix, marius).
fatherOf(felix, manon).
fatherOf(hans, daniel).
fatherOf(hans, felix).
fatherOf(opa, lorle).

siblings(X, Y) :-
	motherOf(M, X),
	motherOf(M, Y),
	fatherOf(F, X),
	fatherOf(F, Y),
	X \= Y.

parentOf(X, Y) :- motherOf(X, Y).
parentOf(X, Y) :- fatherOf(X, Y).

grandmotherOf(X, Z) :-
	motherOf(X, Y),
	parentOf(Y, Z).

ancestor(X, Y) :- parentOf(X, Y).
ancestor(X, Z) :-
	parentOf(X, Y),
	ancestor(Y, Z).

cousins(X, Y) :-
	parentOf(PX, X),
	parentOf(PY, Y),
	siblings(PX, PY).