Subject: RE: Compatibility of the AFL with the GPL
From: "Lawrence E. Rosen" <>
Date: Fri, 14 Mar 2003 19:39:30 -0800


Sorry to have to knock that leg of the chair out from under you, but I
actually believe that the AFL license *does* apply to the portion of a
derivative work that consists of the work originally licensed under the
AFL.  Eben and I agree on that.  So really, there are two licenses that
the licensee is operating under, the GPL and the AFL.  This is because
the AFL-licensed software is not sublicenseable.  It remains under its
original license, even though the combination (e.g., collective or
derivative work) is under the GPL.  

What is important is to determine whether the mutual defense provision
in the AFL makes the two licenses incompatible.  But I'm convinced it
really doesn't.  Assume someone sues the AFL program for patent
infringement.  Even before one can raise the AFL mutual defense clause
to stop distribution of the AFL component of the GPL program, the GPL
program automatically can't be distributed because of section 7 of the
GPL.  The AFL mutual defense pass-through is just icing on the cake.
The two licenses are more compatible than some people have realized.

That's why the term "compatibility" has been such a sore point for me.
You can't just look at the plain language of the licenses, you have to
think through the legal effects of the combination of the language of
two licenses.  Of course the mutual defense provision isn't in the GPL.
That is, literally, an incompatibility of words.  But the end result is
the same whether the AFL passes-through or not.

/Larry Rosen

> -----Original Message-----
> From: Russell Nelson [] 
> Sent: Friday, March 14, 2003 7:20 PM
> To:;; 'Eben Moglen'
> Subject: Re: Compatibility of the AFL with the GPL 
> Greg Pomerantz writes:
>  > > Lawrence E. Rosen writes:
>  > >  > OK, guys, play with me one more round.  This time, 
> let's do it in the  > >  > form of a law school exam question 
> and let's get the lawyers and IANALs  > >  > on this list to 
> chime in:  > > 
>  > > Nahhh.  None of this is necessary.  There's nothing in 
> the AFL that  > > says that you must use the same license on 
> derivative works.  > > Therefore, without reference to any 
> other terms of the AFL, it is  > > trivially compatible with 
> the GPL insofar as derivative works get  > > licensed under 
> the GPL.  > 
>  > Russ, the AFL is not sublicensable. If you're using AFL 
> code (or a  > derivative of AFL code), you need a license 
> from the author,  > regardless of who you got that code from.
> One of the things you're allowed to do under the AFL is 
> create derivative works.  There is nothing in the AFL which 
> requires you to license that work under the AFL (unlike the 
> GPL, which *does* require GPL'ed derivative works).  So, when 
> you get an AFL-licensed work, you also receive a license from 
> the copyright holder, licensing you to do whatever you want, 
> modulo abusing trademarks, or suing Mutual Defense licensors. 
>  Does that bind anybody who received a copy of your 
> derivative work?  No, because that work is licensed under the 
> GPL, and the AFL very specifically says that Mutual Defense 
> only applies if the license says Mutual Defense.  The GPL 
> doesn't, and so while *you* lose your license to distribute, 
> the people you have distributed the GPL'ed work to don't.  
> Does it now suck to be you?  Yes, and you should have thought 
> about that *before* you sued.
> Many and subtle are the powers of Larry Rosen.
> -- 
> -russ nelson   | "What 
> Problem Are You Trying
> Crynwr sells support for free software  | PGPok | To Solve?" 
> is a service mark 521 Pleasant Valley Rd. | +1 315 268 1925 
> voice | of Crynwr Software.
> Potsdam, NY 13676-3213  | +1 315 268 9201 FAX   | 
> --
> license-discuss archive is at

license-discuss archive is at