Re: Swiss Ephemeris Public License

[Edmund GRIMLEY EVANS <edmundo@rano.org>]

Anthony DeRobertis <asd@suespammers.org>:

> >You seem to be saying that A and C are DFSG-free, but B isn't. So
> >something released with license A is free, but software dual-licensed
> >with A and B is non-free. I seem to be seeing or imagining some kind
> >of paradox here ...
> 
> Given:
>         A := BSD to all
>         B := BSD to few, GPL rest
>         C := GPL to all
>         
>         A => free
>         C => free
>         
> Now, "Dual licensed under A and B" means "A OR B", so we can conclude:
>         A OR B => free
>         C OR B => free
>         
> However, without further "givens", we can logically conclude *nothing*
> about B.

So you disagree with the claim that dual-licensing something under A
and B is the same as licensing it under B?

Note that your Pascal-style assignments could be misunderstood. For
example, licence B does not grant a GPL-licence for the original work
to anyone; it merely requires that modifications be released under the
GPL. Similary A, does not grant a BSD-licence for the original work;
it merely requires modifications to be BSD-licensed (thus allowing the
original authors to take those modifications proprietary).

> I think the apparent paradox is coming from confusing "dual license" to
> mean "AND" instead of "OR".

I don't think so, but the words AND and OR don't mean much in
isolation, anyway. (It's all a question of at whose option ...)