%%
%% From https://www.doc.ic.ac.uk/~mpd37/teaching/2014/ml_tutorials/2014-10-15-wood-anglican.pdf
%% Page 34ff
%% """
%% Symbolic Function Induction
%% What’s the next value? And the function?
%%
%% Input    Output
%% ---------------
%% 1        5
%% 2        3
%% 3        1
%% 4        ?
%%
%% The answer should be -1:
%%   7- 2*X
%%
pos(f(1,5)).
pos(f(2,3)).
pos(f(3,1)).
% pos(f(4,X)). % What is X?

neg(f(4,1)).