[sf-lug] need advice: GPL licensing question

[Catherine Jones]

Just went to hear RMS and came away enlightened but confused.

Here's my problem. I'm writing a textile-design program (pre-alpha
tarball available at patternand.org) that the requires following to
run:

(1) my own Python code (released under GPL v3)

(2) some files I wrote containing numerical data in XML format; this
    data describes some sample polygons and ways to arrange them on a
    flat surface - ideas that I believe (and hope) are common math
    knowledge in the public domain

My question: how should I deal with item (2) above?

Right now the numerical data files included in the tarball contain
some labor - it took work to write them - but not original ideas.
They're not code so much as mindless transcription of existing math
ideas into a particular XML format I devised, a format deducible from
my Python code.

Currently there's a great ambiguity. The tarball includes the standard
COPYING file containing the GPL v3 license. The Python files in the
tarball have individual GPL v3 copyright notices attached, but the XML
data files don't. Should they have some kind of copyright notice
attached - maybe a Creative Commons license that's compatible with GPL
v3? 

While the current XML data files are just examples to show how the
program works, I may in the future want to incorporate into the
program XML data files (mine or another contributor's) that contain
some real artistic or mathematical creativity. What should I do share
such content and keep it part of the commons? Any help welcome....

Catherine