% From https://github.com/michael-siebers/metagol/blob/ilp2018/examples/leapyear1.pl
%% background knowledge

% """
% This is equivalent to B_max described in the paper.
% Please note that possible dividers were computed as
% pre-processing step in the experiments.
% """
% hakank: These are the divisors of 400.
known_divider(1).
known_divider(2).
known_divider(4).
known_divider(5).
known_divider(8).
known_divider(10).
known_divider(16).
known_divider(20).
known_divider(25).
known_divider(40).
known_divider(50).
known_divider(80).
known_divider(100).
known_divider(200).
known_divider(400).

known([1,2,3,5,8,10,16,20,25,40,50,80,100,200,400]).

divisible(X,Y) :- 
        nonvar(X),
        % (nonvar(Y) ; member(Y,known)), % This does not work
        (nonvar(Y); known_divider(Y)), % This works
        X mod Y =:= 0.

not_divisible(X,Y) :- 
        nonvar(X),
        % (nonvar(Y) ; member(Y,known)), % Does not work
        (nonvar(Y); known_divider(Y)), % This works
        X mod Y =\= 0.

%% tell metagol to use the BK
prim(divisible/2).
prim(not_divisible/2).



eq(X,Y) :- X =:= Y.