Add the \directsum operator.

diff --git a/mjo-common.tex b/mjo-common.tex
index 408ca3310e7dbff8e498936e4bfefbe77e49c483..0a9a5d206941c55346153e22bc0b41a8c7cc4510 100644 (file)
--- a/mjo-common.tex
+++ b/mjo-common.tex
@@ -29,6 +29,9 @@
 % The Cartesian product of three things.
 \providecommand*{\cartprodthree}[3]{ \cartprod{{#1}}{\cartprod{{#2}}{{#3}}} }
 
+% The direct sum of two things.
+\providecommand*{\directsum}[2]{ {#1}\oplus{#2} }
+
 % The factorial operator.
 \providecommand*{\factorial}[1]{ {#1}! }