Prolog Lab 2
       University of Wales, Cardiff   
 
   This exercise is not assessed, but it is in your interest to
practise this, because SOON there might be one that is.   

1. Consider the following program :             

  
parent_of(mary, peter).
parent_of(james, peter).
parent_of(mary, eunice).
parent_of(james, eunice).
parent_of(mary, lois).
parent_of(james, lois).
parent_of(marion, mary).
parent_of(timothy, mary).
parent_of(paul, timothy).
parent_of(marion, anna).
parent_of(jack, jill).
parent_of(mick, liam).
parent_of(clare, steve).

male(peter).
male(james).
male(timothy).
male(paul).
male(steve).
male(jack).
male(mick).
male(liam).

female(mary).
female(eunice).
female(lois).
female(marion).
female(anna).
female(clare).
female(jill).

mother_of(Mother, Person) :-
 parent_of(Mother, Person),
 female(Mother).
 
mother_of2(Person) :-
 parent_of(Mother, Person),
 female(Mother).

grandad_of(Granpa, Person) :-
 parent_of(Parent, Person),
 parent_of(Granpa, Parent),
 male(Granpa).

 

 
   Who is mary's mother, and eunice's grandfather. 
   Modify the    grandad of  relation for a    grandma of 
relation.
   What is the difference between the two mother of relations. 
   Write predicates and clauses for the following :  
   child of(Child, Person)   
which succeeds if    Child  is a son of    Person . 
 
   son of(Son, Person)   
which succeeds if    Son  is a son of    Person .  
 
   brother of(Brother, Person)   
which succeeds if    Brother  is a brother of a    Person 
  Can you draw the tree to show how backtracking occurs 
in this case ? Also, how are multiple solutions obtained ?
A diagram to show the workings of this program would be useful
to visualise program behaviour.
 

   Note: the facts within the database may have to be expanded
for some of the relations to be written .