double_negation.lp
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%not not a.
%% UNSATISFIABLE
%%% ie no models.
% a.
%% Answer: 1
%% a
%% SATISFIABLE
%%% ie there is (only) one (stable) model: {a}
% -a.
%% Answer: 1
%% -a
%% SATISFIABLE
% --a.
%% *** ERROR: (clingo): parsing failed
%%% WTF?
% not a.
%% Answer: 1
%%
%% SATISFIABLE
%%% ie there is (only) one (stable) model: {}
%%%
%%% this program states that there is no information. In particular, there is no information about a.
%%% Therefore there are no provable atoms. Hence the empty set is a stable model.
% not -a.
%% Answer: 1
%%
%% SATISFIABLE
% b.
% a;c.
% not a :- b.
%% Answer: 1
%% b -a
%% SATISFIABLE
a.
b :- not a.