On Mon, Feb 13, 2012 at 3:35 AM, Dr. David Kirkby
Post by Dr. David Kirkby Post by Dr. David Kirkby
Since some of packages will not have the "or later version" added into
the license, we can't distribute Sage as GPL 3 or even "GPL 2 or any
later version", since some of the components don't have the "or any
Which packages are those? I thought we were being really careful to not
include any packages that were GPLv2 only in the base, standard
distribution of Sage?
Or are you just imagining that there probably is such a package?
gfan is GPLv2+.
I know the author of gfan personally; I don't remember for sure, but I
think got him to GPL it in the first place. All he did was take his
code and put the standard GPL "COPYING" file (which has the GPLv2
license in it) in the same directory, and include a LICENSE file that
deep:src wstein$ more LICENSE
The Gfan software is distributed under the "GNU GENERAL PUBLIC
LICENSE" as described in the file "COPYING".
Ask the author if you want a more reasonable license.
Because the LICENSE file (and code) do not specifically state that the
program is GPLv2, one may use any version of the GPL license (>= 2).
I'm not comfortable with this statement: "IMHO, if you want to be
totally legal, then you should not use Sage." It seems like FUD that
ignores a ton of hard work that we have all done campaigning to get
licenses changed, sometimes choosing a much more difficult path
(regarding which libraries we use) just because of GPL versions, etc.
To the best of my knowledge there is not ** ONE SINGLE PACKAGE **
included with Sage that is licensed GPLv2 only. If this is not
actually the case, I really want to know about it. I believe that
Sage is 100% legally distributed and does not violate any copyright
statements at all.
That said, it would be good to change the line in *our* SPKG.txt for
gfan that says:
"== License ==
* GPL v2"
This line was added in 2010 by Alex Ghitza and positively reviewed by
Marshal Hampton. They claimed to be dealing with trac #3043 (from 4
years ago) which specifically asked for clarification of this. The
first comment on trac #3043 was by Michael Abshoff (who has actually
read the GPL) where he explained very clearly exactly how things work
with GPL, and that the software is GPLv2+. Then Alex seems to have
ignored or misinterpreted Michael's remark with "I would say that's
pretty clear"... since maybe he hasn't so closely read the GPL.
So please review: http://trac.sagemath.org/sage_trac/ticket/12504
Post by Dr. David Kirkby
= gfan =
== Description ==
Gfan is a software package for computing Groebner fans and tropical varieties.
These are polyhedral fans associated to polynomial ideals. The maximal cones
of a Groebner fan are in bijection with the marked reduced Groebner bases of
its defining ideal. The software computes all marked reduced Groebner bases of
an ideal. Their union is a universal Groebner basis. The tropical variety of a
polynomial ideal is a certain subcomplex of the Groebner fan. Gfan contains
algorithms for computing this complex for general ideals and specialized
algorithms for tropical curves, tropical hypersurfaces and tropical varieties
of prime ideals. In addition to the above core functions the package contains
many tools which are useful in the study of Groebner bases, initial ideals and
== License ==
* GPL v2
This is COPYING in the source.
GNU GENERAL PUBLIC LICENSE
Version 2, June 1991
Copyright (C) 1989, 1991 Free Software Foundation, Inc.
675 Mass Ave, Cambridge, MA 02139, USA
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