Homework SourseUSE RESOLUTION to prove WIRTHS statement I married a widow W
USE RESOLUTION to prove WIRTH\'S statement.
I married a widow W who has a grown-up daughter D. My father F fell in love with my-daughter and married her. Hence my father became my son-in-law and my step-daughter became my step-mother. Some months later, my wife gave birth to a son S1, who became the brother-in-law of my father, as well as my uncle. The wife of my father, that is, my step-daughter, had a son S2.
Solution
aunt(X,Y):-
sibling(X,Z),
parent(Z,Y),
female(X).
brother(X,Y):-
sibling(X,Y),
male(X).
brother_in_law(X,Y):-
child(X,Z),
married(Z,W),
parent(W,Y),
not(sibling(X,Y)),
male(X).
brother_in_law(s1,f).
child(X,Y):-
parent(Y,X).
daughter(X,Y):-
parent(Y,X),
child(X,Y),
female(X).
daughter(d,w).
father(X,Y):-
parent(X,Y),
male(X).
father(f,i).
father_in_law(X,Y):-
child(X,Z),
married(Y,Z),
not(child(X,Y)),
male(X).
grandparent(X,Y):-
parent(X,Z),
parent(Z,Y).
grandmother(X,Y):-
grandparent(X,Y),
female(X).
grandfather(X,Y):-
grandparent(X,Y),
male(X).
grandchild(X,Y):-
child(X,Z),
child(Z,Y).
married(X,Y):-
wife(X,Y),
female(X).
married(X,Y):-
husband(X,Y),
male(X).
married(i,w).
married(f,d).
mother(X,Y):-
parent(X,Y),
female(X).
parent(X,Y):-
child(Y,X).
sibling(X,Y):-
parent(Z,X),
parent(Z,Y).
sister(X,Y):-
sibling(X,Y),
female(X).
son(X,Y):-
parent(Y,X),
male(X).
son(s1,w).
son(s2,d).
son_in_law(X,Y):-
child(X,Z),
not(child(X,Y)),
married(Z,Y),
male(X).
son_in_law(f,i).
step_daughter(X,Y):-
child(X,Z),
married(Z,Y),
not(child(X,Y)),
female(X).
step_daughter(d,i).
step_parent(X,Y):-
married(X,Z),
parent(Z,Y),
not(parent(X,Y)).
step_father(X,Y):-
step_parent(X,Y),
male(X).
step_mother(X,Y):-
step_parent(X,Y),
female(X).
step_mother(d,i).
uncle(X,Y):-
sibling(X,Z),
parent(Z,Y),
male(X).
uncle(s1,i).
