X-Git-Url: http://gitweb.michael.orlitzky.com/?a=blobdiff_plain;f=mjo-common.tex;h=b269417749dcf12738b968645a0083c7aa033ed2;hb=90b275219d518d1c851c71c87484c1a3385f3b70;hp=0a9a5d206941c55346153e22bc0b41a8c7cc4510;hpb=58dd2634228390d7a902edf9bf70570e22ebbf4e;p=mjotex.git

diff --git a/mjo-common.tex b/mjo-common.tex
index 0a9a5d2..b269417 100644
--- a/mjo-common.tex
+++ b/mjo-common.tex
@@ -23,6 +23,9 @@
 % A pair of things.
 \providecommand*{\pair}[2]{ \left({#1},{#2}\right) }
 
+% A triple of things.
+\providecommand*{\triple}[3]{ \left({#1},{#2},{#3}\right) }
+
 % The Cartesian product of two things.
 \providecommand*{\cartprod}[2]{ {#1}\times{#2} }
 
@@ -68,3 +71,20 @@
 \providecommand*{\Cn}[1][n]{
   \mathbb{C}\if\detokenize{#1}\detokenize{1}{}\else^{#1}\fi
 }
+
+
+%
+% Basic set operations
+%
+
+% The union of its two arguments.
+\providecommand*{\union}[2]{ {#1} \cup {#2} }
+
+% A three-argument union.
+\providecommand*{\unionthree}[3]{ \union{\union{#1}{#2}}{#3} }
+
+% The intersection of its two arguments.
+\providecommand*{\intersect}[2]{ {#1} \cap {#2} }
+
+% A three-argument intersection.
+\providecommand*{\intersectthree}[3]{ \intersect{\intersect{#1}{#2}}{#3} }