Copyright (C) 2000, Luca Padovani <luca.padovani@cs.unibo.it>.

This file is part of HELM, an Hypertextual, Electronic
Library of Mathematics, developed at the Computer Science
Department, University of Bologna, Italy.

HELM is free software; you can redistribute it and/or
modify it under the terms of the GNU General Public License
as published by the Free Software Foundation; either version 2
of the License, or (at your option) any later version.

HELM is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
GNU General Public License for more details.

You should have received a copy of the GNU General Public License
along with HELM; if not, write to the Free Software
Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA  02111-1307, USA.

For details, see the HELM World-Wide-Web page,
http://cs.unibo.it/helm/.