% greekctr.sty
% 15. Juni 1990, revised 3-jan-1996
% For additional information look after \endinput
\NeedsTeXFormat{LaTeX2e}
\ProvidesPackage{greekctr}[1996/01/03 Greek Counterstyle (jk)]
\RequirePackage{amstext}
\def\greek#1{\@greek{\@nameuse{c@#1}}}
\def\@greek#1{\ifcase#1\or{\text{$\alpha$}}\or{\text{$\beta$}}\or%
  {\text{$\gamma$}}\or{\text{$\delta$}}\else\@igreek{#1}\fi}
\def\@igreek#1{\ifcase#1\or\or\or\or\or{\text{$\varepsilon$}}%
  \or{\text{$\zeta$}}\or{\text{$\eta$}}\or{\text{$\vartheta$}}%
  \or{\text{$\iota$}}\or{\text{$\kappa$}}\or{\text{$\lambda$}}\or%
  {\text{$\mu$}}\or{\text{$\nu$}}\or%
  {\text{$\xi$}}\or{\text{$o$}}\or{\text{$\pi$}}\or{\text{$\varrho$}}%
  \or{\text{$\sigma$}}\or{\text{$\tau$}}\or{\text{$\upsilon$}}\or%
  {\text{$\varphi$}}\or{\text{$\chi$}}\or%
  {\text{$\psi$}}\or{\text{$\omega$}}\else {\text{$\omega$}}\@ctrerr\fi} 
\def\Greek#1{\@Greek{\@nameuse{c@#1}}}
\def\@Greek#1{\ifcase#1\or A\or B\or\text{$\Gamma$}\or%
  \text{$\Delta$}\else\@iGreek{#1}\fi}
\def\@iGreek#1{\ifcase#1\or\or\or\or\or E\or Z\or H\or\text{$\Theta$}\or%
  I\or K\or\text{$\Lambda$}\or M\or N\or\text{$\Xi$}\or O\or%
  \text{$\Pi$}\or P\or\text{$\Sigma$}\or T\or\text{$\Upsilon$}\or%
  \text{$\Phi$}\or X\or\text{$\Psi$}\else\text{$\Omega$}\@ctrerr\fi}
\endinput

Usage:

\renewcommand{\the<counter>}{\greek{<counter>}}
\renewcommand{\the<counter>}{\Greek{<counter>}}

e.g. \renewcommand{\theenumi}{\greek{enumi}}

Provides \greek and \Greek for counters just like \alph. No switch to 
math mode is needed. \varepsilon, \vartheta and \varphi are preferred, 
but \pi and \sigma.

(c) Copyright 1990, 1996 J"org Knappen. All rights reserved.

This file may be distibuted via anonymous ftp servers and by non-profit
organisation like DANTE e.V., TUG, etc.

You are allowed to distribute this file, as long as you
 
a) distribute unchanged files ony, leaving this notice intact
b) take no money for it, except for a nominal charge

J"org Knappen, Barbarossaring 43, D-55118 Mainz, Allemagne. 
Internet: [email protected]