<?xml version="1.0"?>
<!DOCTYPE para PUBLIC "-//OASIS//DTD DocBook XML V4.1.2//EN" "http://www.oasis-open.org/docbook/xml/4.1.2/docbookx.dtd">
<para>
The equation e<superscript>πi</superscript> + 1 = 0 ties together
five of the most important mathematical constants.
</para>
