mjo-algebra: add \Stab command for stabilizer subgroups.

diff --git a/examples.tex b/examples.tex
index 740dd02f473945597cb4f0b42893a456f71011a7..d8e2c3243f85d436f2600267c21475556a75b99f 100644 (file)
--- a/examples.tex
+++ b/examples.tex
@@ -39,7 +39,8 @@
 
     If $R$ has a multiplicative identity (that is, a unit) element,
     then that element is denoted by $\unit{R}$. Its additive identity
-    element is $\zero{R}$.
+    element is $\zero{R}$. The stabilizer (or isotropy)
+    subgroup of $G$ that fixes $x$ is $\Stab{G}{x}$.
   \end{section}
 
   \begin{section}{Algorithm}

diff --git a/mjo-algebra.tex b/mjo-algebra.tex
index 25b96d9f8a184edc051ed2867bc8fa9b4b0a269b..1ab88806c2cdad1caa64bfb62ea860496e820db9 100644 (file)
--- a/mjo-algebra.tex
+++ b/mjo-algebra.tex
@@ -90,4 +90,8 @@
 \fi
 
 
+% The stabilizer subgroup of its first argument that fixes the point
+% given by its second argument.
+\newcommand*{\Stab}[2]{ #1_{#2} }
+
 \fi