1% Basic Event Calculus
    2
    3%% Include the BASIC EVENT CALCULUS THEORY
    4#include 'bec_theory.incl'.
    5
    6is_1_day_after(B, A) :- B #= A + 1.
    7
    8%% based on the loan agreement example in Logical English
    9initiates(ends(A), it_is(B), _) :-
   10    is_1_day_after(B, A).
   11initiates(ends(1), is_liable_to_litigation(the_lender), A) :-
   12    holdsAt(requested_on(the_borrower, 1000, 2), A),
   13    not holdsAt(advanced_on(the_lender, 1000, _), 1).
   14initiates(ends(2), is_terminated(the_agreement), _) :-
   15    not holdsAt(requested_on(the_borrower, 1000, 2), 2).
   16initiates(requests(the_borrower, A), requested_on(the_borrower, A, B), B).
   17initiates(advances(the_lender, A), advanced_on(the_lender, A, B), B).
   18initiates(ends(_), is_potentially_defaulted(B), A) :-
   19    B=pays_to(C, D, E),
   20    is_due_on_from_to(D, A, C, E),
   21    holdsAt(it_is(F), F),
   22    not holdsAt(paid_to_on(C, D, E, _), F).
   23initiates(pays_to(A, B, C), paid_to_on(A, B, C, D), D).
   24
   25is_due_on_from_to(550, 4, the_borrower, the_lender).
   26is_due_on_from_to(525, 5, the_borrower, the_lender).
   27
   28%% Actions
   29
   30happens(ends(1), 1).
   31happens(ends(2), 2).
   32happens(requests(the_borrower, 1000), 2).
   33
   34?- holdsAt(F, T).