\documentclass[a4paper,10pt]{article}
\usepackage{amssymb}
\usepackage{textcomp}

% %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
% Author: Thomas Braun
% begin: Sat 8 april 2006
% last edit: So 1 april 2007
% License: GPLv2 or later
% %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%

\input{definitions}

\iffalse
\newcommand{\begin{neededpkgs}}[2][]{}
\newcommand{\pkgs}[2][]{}
\fi

\begin{document}

\mathcommand{\leftarrow}
\mathcommand{\leftrightarrow}
\mathcommand{\rightarrow}
\mathcommand{\mapsto}
\mathcommand{\longleftarrow}
\mathcommand{\longleftrightarrow}
\mathcommand{\longrightarrow}
\mathcommand{\longmapsto}

\mathcommand{\downarrow}
\mathcommand{\updownarrow}
\mathcommand{\uparrow}
\mathcommand{\nwarrow}
\mathcommand{\searrow}
\mathcommand{\nearrow}
\mathcommand{\swarrow}

\begin{neededpkgs}{textcomp}
\command{\textdownarrow}
\command{\textuparrow}
\command{\textleftarrow}
\command{\textrightarrow}
\end{neededpkgs}
\begin{neededpkgs}{amssymb}
\mathcommand{\nleftarrow}
\mathcommand{\nleftrightarrow}
\mathcommand{\nrightarrow}
\end{neededpkgs}

\par\bigskip

\mathcommand{\hookleftarrow}
\mathcommand{\hookrightarrow}
\begin{neededpkgs}{amssymb}
\mathcommand{\twoheadleftarrow}
\mathcommand{\twoheadrightarrow}
\mathcommand{\leftarrowtail}
\mathcommand{\rightarrowtail}
\end{neededpkgs}

\par\bigskip

\mathcommand{\Leftarrow}
\mathcommand{\Leftrightarrow}
\mathcommand{\Rightarrow}
\mathcommand{\Longleftarrow}
\mathcommand{\Longleftrightarrow}
\mathcommand{\Longrightarrow}
\mathcommand{\Updownarrow}
\mathcommand{\Uparrow}
\mathcommand{\Downarrow}
\begin{neededpkgs}{amssymb}
\mathcommand{\nLeftarrow}
\mathcommand{\nLeftrightarrow}
\mathcommand{\nRightarrow}
\end{neededpkgs}

\par\bigskip

\begin{neededpkgs}{amssymb}
\mathcommand{\leftleftarrows}
\mathcommand{\leftrightarrows}
\mathcommand{\rightleftarrows}
\mathcommand{\rightrightarrows}
\mathcommand{\downdownarrows}
\mathcommand{\upuparrows}
\end{neededpkgs}

\par\bigskip

\begin{neededpkgs}{amssymb}
\mathcommand{\circlearrowleft}
\mathcommand{\circlearrowright}
\mathcommand{\curvearrowleft}
\mathcommand{\curvearrowright}
\mathcommand{\Lsh}
\mathcommand{\Rsh}
\mathcommand{\looparrowleft}
\mathcommand{\looparrowright}
\end{neededpkgs}

\par\bigskip

\begin{neededpkgs}{amssymb}
\mathcommand{\dashleftarrow}
\mathcommand{\dashrightarrow}
\mathcommand{\leftrightsquigarrow}
\mathcommand{\rightsquigarrow}
\mathcommand{\Lleftarrow}
\end{neededpkgs}

\par\bigskip

\mathcommand{\leftharpoondown}
\mathcommand{\rightharpoondown}
\mathcommand{\leftharpoonup}
\mathcommand{\rightharpoonup}
\mathcommand{\rightleftharpoons}
\begin{neededpkgs}{amssymb}
\mathcommand{\leftrightharpoons}
\mathcommand{\downharpoonleft}
\mathcommand{\upharpoonleft}
\mathcommand{\downharpoonright}
\mathcommand{\upharpoonright}
\end{neededpkgs}

\par\bigskip

\end{document}
