From 123eb0365b7a38288f0cd80a0c70b203b8ff33fd Mon Sep 17 00:00:00 2001
From: Michael Orlitzky <michael@orlitzky.com>
Date: Sun, 3 Nov 2019 21:50:56 -0500
Subject: [PATCH] mjo-common: utilize \mathpzc to finally define \powerset{}.

---
 TODO           |  5 +----
 examples.tex   |  6 ++++--
 mjo-common.tex | 12 +++++++++---
 3 files changed, 14 insertions(+), 9 deletions(-)

diff --git a/TODO b/TODO
index f2caa9e..ddde006 100644
--- a/TODO
+++ b/TODO
@@ -1,7 +1,4 @@
 1. Move the set operations from mjo-common and mjo-misc into mjo-set.
 
-2. Add a \powerset command, once I decide whether to use \mathcal{P}
-   or 2^{X} for the notation.
-
-3. Having S^{n} or H^{n} reduce to simply "S" or "H" in the case where
+2. Having S^{n} or H^{n} reduce to simply "S" or "H" in the case where
    n=1 doesn't make sense.
diff --git a/examples.tex b/examples.tex
index e1f375f..cd615de 100644
--- a/examples.tex
+++ b/examples.tex
@@ -112,6 +112,7 @@
     \begin{equation*}
       \directsummany{k=1}{\infty}{V_{k}} \ne \cartprodmany{k=1}{\infty}{V_{k}}.
     \end{equation*}
+    %
     Here are a few common tuple spaces that should not have a
     superscript when that superscript would be one: $\Nn[1]$,
     $\Zn[1]$, $\Qn[1]$, $\Rn[1]$, $\Cn[1]$. However, if the
@@ -130,8 +131,9 @@
     \begin{equation*}
       \unionmany{k=1}{\infty}{A_{k}} = \intersectmany{k=1}{\infty}{B_{k}}
     \end{equation*}
-
-    Finally, we have the four standard types of intervals in $\Rn[1]$,
+    %
+    The powerset of $X$ displays nicely, as $\powerset{X}$. Finally,
+    we have the four standard types of intervals in $\Rn[1]$,
     %
     \begin{align*}
       \intervaloo{a}{b} &= \setc{ x \in \Rn[1]}{ a < x < b },\\
diff --git a/mjo-common.tex b/mjo-common.tex
index 27c4c7b..a8d9aaa 100644
--- a/mjo-common.tex
+++ b/mjo-common.tex
@@ -5,9 +5,7 @@
 \def\havemjocommon{1}
 
 
-\ifx\mathbb\undefined
-  \usepackage{amsfonts}
-\fi
+\input{mjo-font} % amsfonts and \mathpzc
 
 \ifx\bigtimes\undefined
   \usepackage{mathtools}
@@ -200,6 +198,14 @@
 \newcommand*{\directsummany}[3]{ \binopmany{\bigoplus}{#1}{#2}{#3} }
 \newcommand*{\unionmany}[3]{ \binopmany{\bigcup}{#1}{#2}{#3} }
 
+\newcommand*{\powerset}[1]{\mathpzc{P}\of{{#1}}}
+\ifdefined\newglossaryentry
+  \newglossaryentry{powerset}{
+    name={\ensuremath{\powerset{X}}},
+    description={the ``powerset,'' or set of all subsets of $X$},
+    sort=p
+  }
+\fi
 
 % The four standard (UNLESS YOU'RE FRENCH) types of intervals along
 % the real line.
-- 
2.44.2