mjo-linear_algebra.tex: add \rref{} macro.

diff --git a/examples.tex b/examples.tex
index 015c5fd67df5aa3e5d4c272c60480694d20ba1ba..babc886abe26b31ef223cb783e2fa43d4d848d79 100644 (file)
--- a/examples.tex
+++ b/examples.tex
@@ -203,7 +203,8 @@
     instead.
 
     If you want to solve a system of equations, try Cramer's
-    rule~\cite{ehrenborg}.
+    rule~\cite{ehrenborg}. Or at least the reduced row-echelon form of
+    the matrix, $\rref{A}$.
 
     The direct sum of $V$ and $W$ is $\directsum{V}{W}$, of course,
     but what if $W = V^{\perp}$? Then we wish to indicate that fact by

diff --git a/mjo-linear_algebra.tex b/mjo-linear_algebra.tex
index a534523765ef1fd20f7729af25836bb2075fcd3e..7f2484a546ef750977ca2b4c1ab7ae451a66f122 100644 (file)
--- a/mjo-linear_algebra.tex
+++ b/mjo-linear_algebra.tex
@@ -89,6 +89,16 @@
   }
 \fi
 
+% The reduced row-echelon form of its argument, a matrix.
+\newcommand*{\rref}[1]{\operatorname{rref}\of{#1}}
+\ifdefined\newglossaryentry
+  \newglossaryentry{rref}{
+    name={\ensuremath{\rref{A}}},
+    description={the reduced row-echelon form of $A$},
+    sort=r
+  }
+\fi
+
 % The ``Automorphism group of'' operator.
 \newcommand*{\Aut}[1]{ \operatorname{Aut}\of{{#1}} }