\documentstyle[a4,12pt]{article}

\title{Some Special Symbols}
%\author{John Glauert}
\author{}
\date{}
%\reportref{Draft}

\newcommand{\twoheadrightarrow}{\rightarrow\kern-.8em\rightarrow}

\begin{document}
\maketitle

\section*{Symbols}

From Lamport we have
\begin{eqnarray*}
\verb| $\lhd$ | & \longrightarrow & \lhd \\
\verb| $\unlhd$ | & \longrightarrow & \unlhd \\
\end{eqnarray*}

We can also use \verb|$\stackrel$| to stack pairs of characters:

\begin{eqnarray*}
\verb| $\stackrel{a}{=}$ | & \longrightarrow & \stackrel{a}{=} \\
\verb| $\stackrel{\triangle}{-}$ | & \longrightarrow & \stackrel{\triangle}{-} \\
\end{eqnarray*}

That doesn't seem much good. We can also underline characters:

\begin{eqnarray*}
\verb| $\underline{\triangle}$ | & \longrightarrow & \underline{\triangle} \\
\verb| $\underline{\lhd}$ | & \longrightarrow & \underline{\lhd} \\
\end{eqnarray*}

Here is a use of my twoheadrightarrow:

\begin{eqnarray*}
\verb| $\twoheadrightarrow$ | & \longrightarrow & t\twoheadrightarrow s \\
\end{eqnarray*}

\end{document}
