% Graph generator 

#hide.
#show arc(X,Y).        %%output
#domain node(X;Y;Z).

node(1..n).

{ arc(X,Y) } :- node(X), node(Y). %% all directed graphs

% :- arc(X,X).                    %% irreflexive
% arc(Y,X) :- arc(X,Y).           %% symmetric
% :- arc(Y,X), arc(X,Y).          %% asymmetric
% arc(X,Y) :- arc(X,Z), arc(Y,Z). %% Euclidean edge relation