X-Git-Url: http://gitweb.michael.orlitzky.com/?p=mjotex.git;a=blobdiff_plain;f=mjo-linear_algebra.tex;fp=mjo-linear_algebra.tex;h=c57e9b9534309d70d760540ba464b94511a1f085;hp=d493b9cce5bd047eeb940a972128a6cf7198d261;hb=10b83af54da036b9f3122b5e82b18816c5acf386;hpb=8f1fcf7f68cfd450c4374524a16a92bf610edc9c

diff --git a/mjo-linear_algebra.tex b/mjo-linear_algebra.tex
index d493b9c..c57e9b9 100644
--- a/mjo-linear_algebra.tex
+++ b/mjo-linear_algebra.tex
@@ -51,6 +51,11 @@
 % The trace of an operator.
 \newcommand*{\trace}[1]{ \operatorname{trace}\of{{#1}} }
 
+% The diagonal matrix whose only nonzero entries are on the diagonal
+% and are given by our argument. The argument should therefore be a
+% vector or tuple of entries, by convention going from the top-left to
+% the bottom-right of the matrix.
+\newcommand*{\diag}[1]{\operatorname{diag}\of{{#1}}}
 
 % The "rank" of its argument, which is context-dependent. It can mean
 % any or all of,