:- use_module(library(pitaind)).
:- pitaind.
:- begin_lpad.


advisedby(A,B) : 0.3 :-
    student(A), professor(B), project(C, A), project(C, B),
    r11(A, B, C).
/*
advisedby(A,B) : 0.6 :-
    student(A), professor(B), ta(C, A), taughtby(C,B).
*/
r11(A, B, C) : 0.2 :-
    publication(D, A, C), publication(D,B, C).


student(harry).
professor(ben).
project(pr1, harry).
project(pr1, ben).
project(pr2, harry ).
project(pr2, ben).
ta(c1, harry ).
ta(c2, harry ).
taughtby(c1, ben).
taughtby(c2, ben).

publication(p1, harry , pr1).
publication(p1, ben, pr1).
publication(p2, harry , pr1).
publication(p2, ben, pr1).
publication(p3, harry , pr2).
publication(p3, ben, pr2).
publication(p4, harry , pr2).
publication(p4, ben, pr2).

:- end_lpad.