%% BAD ASCII
\documentclass[fleqn,leqno]{article}
\usepackage{hypertlabook}
\pdftitle{ASCII Text}
\fixverbatim
\begin{popup}
\begin{verbatim*}
    <3>1. (x - y \in Nat \ {0})  /\  ~(y > x)
      BY <2>1, <2>3, SimpleArithmetic  DEF Inv, TypeOK
    <3>2. QED
      BY <2>1, <3>1, GCD3  DEF Inv, TypeOK, GCDInv, Next
\end{verbatim*}
\end{popup}
\makeasciipopup