On Tue, Jul 14, 2009 at 2:38 PM, Ondrej Certik<[email protected]> wrote:
>
> On Tue, Jul 14, 2009 at 3:27 PM, Pablo De Napoli<[email protected]> wrote:
>>
>> I have left the following comment on the blog...
>>
>> "However, the GPL means that people cannot realistically use SAGE in a
>> commercial tool, either as a platform/runtime, or as an embedded
>> component."
>>
>> What it is the justification for this claim? Why wouldn't the GPL
>> allow one to use SAGE as a "commercial tool"?
>> I think that a GPL program like Sage might well have commercial
>> applications. For instance: you could use Sage for modelling an
>> industrial process. There is nothing in the GPL against that.

Yes, that comment does seem a little off.  E.g., people use Linux as a
commercial tool, platform, and embedded component in commercial
products all the time.

Anyway, I just posted the following on that blog, which was about the
whole paragraph, which I thought wasn't quite on target.  I
unfortunately made a statement about NZMATH that isn't so nice, but
the fact is that it is the perfect example to illustrate why GPL is a
vastly better choice of license for the Sage project than BSD.  (Short
answer -- because we get to work with the GAP, Singular, maxima, and
PARI projects because we use the GPL license.  If we used BSD we
couldn't.  Working with Gap/Singular/Maxima/PARI rocks.)

I'm the director of the Sage project, and I would like  to clarify a
possible misconception that the following statement you made might
suggest: "SAGE, an open-source Pythonic replacement for
Maple/Mathematica/Magma/Matlab, is another very successful project,
but they staunchly use the GPL. Their reasoning is much like Zed’s,
because the symbolic math software community has been burned in the
past by people profiting from proprietary extensions of BSD code
without attribution or contribution. However, the GPL means that
people cannot realistically use SAGE in a commercial tool, either as a
platform/runtime, or as an embedded component. The SAGE authors have,
presumably, weighed the trade-offs and decided it’s ultimately more
valuable to be protected than to have the contributions of that
segment of developers."

This gives us far too much credit.  In fact, the Sage project uses the
GPL because every single one of the major symbolic mathematics
programs that Sage builds upon --  Maxima, Singular, PARI, NTL, and
GAP -- chose to use the GPL (not LGPL) back in the 1990s.   If it
weren't for Sage building on those projects (and their amazing
communities!), Sage's capabilities would still be quite small in
comparison to Mathematica, Maple, and Magma.   Sage uses the GPL
because we have no choice but to use the GPL.

There is a Python project called NZMATH that was started at the same
time as Sage, is BSD licensed, and original had exactly the same goals
as Sage.  It continues to be excellent evidence that Sage would not
succeed without building on the great work of the GAP, Singular, PARI,
and Maxima projects.  See http://tnt.math.metro-u.ac.jp/nzmath/.

That said, I can understand why you wrote what you wrote above about
why the Sage project uses the GPL.  It was because of a discussion
you, me, and several other people had at Enthought back in 2007, and I
don't want to say that your point is invalid.  It's just that the
situation is really much more complicated than your statement would
suggest.  And I was really tired when we had that discussion.   Also,
you might recall that I committed to BSD license key parts of the Sage
notebook as a result of that conversation (I can do this since the
notebook is totally independent of that mathematics code mentioned
above).

 -- William

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