:- op(700, xfx, [(.=.),(.<>.),(.<.),(.=<.),(.>.),(.>=.)]).
:- op(500, yfx, [..]).
:- op(600, xfy, [ .&. ]).
:- op(700, xfy, [ in ]).
% :- op(700, xfy, [ 'in^' ]).
% :- op(900, xfx, [(equals)]).
