On 2016-08-17, William Stein <wst...@gmail.com> wrote: > If you write a program that genuinely uses the Sage library in a > nontrivial way, then that program is a derived work of Sage
Well, if there is any controversy here, it must be this statement. The question of what constitutes a derived work is subtle and complex, and I don't think any categorical statements are possible. An exploration of this topic that I've found useful is this "Twenty Questions about the GPL": https://jacobian.org/writing/gpl-questions/ I know that various parties have offered their opinions about what constitutes a derived work, including the FSF, the institution behind the GPL. But even the FSF's interpretation isn't binding on anybody -- whether some work falls under the GPL depends on copyright law, which can only be decided by a court, not the you, me, or the FSF, and even then we don't have a whole lot of court cases to guide us. Lay discussions about the GPL tend to contain a lot of wishful thinking alternating with the frank admission that nobody really knows and therefore if there's any question, one must hire a lawyer. Surely, though, a large group of intelligent, motivated people can formulate some clear guidelines. For a start, perhaps sorting out the twenty cases mentioned above into probably yes, probably no, and everything else. Just guessing here; doubtless there are better ideas. Incidentally, if ever a lawyer has weighed in on licensing issues related to Sage, I would be interested to hear about it. Also, I haven't been paying attention, so if there have been previous discussions about the GPL and Sage, I apologize for trotting out a tired argument. FWIW Robert Dodier -- You received this message because you are subscribed to the Google Groups "sage-devel" group. To unsubscribe from this group and stop receiving emails from it, send an email to sage-devel+unsubscr...@googlegroups.com. To post to this group, send email to sage-devel@googlegroups.com. Visit this group at https://groups.google.com/group/sage-devel. For more options, visit https://groups.google.com/d/optout.
