% A three-argument union.
\providecommand*{\unionthree}[3]{ \union{\union{#1}{#2}}{#3} }
% The intersection of its two arguments.
% A three-argument union.
\providecommand*{\unionthree}[3]{ \union{\union{#1}{#2}}{#3} }
% The intersection of its two arguments.
% A three-argument intersection.
\providecommand*{\intersectthree}[3]{ \intersect{\intersect{#1}{#2}}{#3} }
% A three-argument intersection.
\providecommand*{\intersectthree}[3]{ \intersect{\intersect{#1}{#2}}{#3} }
% the upper index, such as \infty. Finally the fourth argument should
% contain the things (e.g. indexed sets) to be operated on.
\providecommand*{\binopmany}[4]{
% the upper index, such as \infty. Finally the fourth argument should
% contain the things (e.g. indexed sets) to be operated on.
\providecommand*{\binopmany}[4]{