:- op(1200, xfx, [+:,-:,+?,-?]).
:- op(760, yfx, #<=>).
:- op(750, xfy, #=>).
:- op(750, yfx, #<=).
:- op(740, yfx, #\/).
:- op(730, yfx, #\).
:- op(720, yfx, #/\).
:- op(710, fy, #\).
:- op(700, xfx, [in,in_set]).
:- op(700, xfx, [#=,#\=,#<,#=<,#>,#>=]).
:- op(550, xfx, ..).
:- op(500, fy, \).
:- op(490, yfx, ?).
:- op(400, yfx, [/>,/<]).