XProc - patent issues?

Recently I was introduced to XProc via a paper written for Balisage 2010.

I was quite astounded. The more I looked at it, XProc appears to be very similar to the language ( Obyx, under GPLv3 ) that I and my colleagues have been authoring (along with it's engine) since March 2003.
Indeed, the very early versions of Obyx had identical keywords (such as source, sink, and so on).

I am now concerned that at some later date, someone may think that we have been using ideas or technologies taken from XProc (which is just not the case) and consider legal actions based on copyright, patent, or other IP issues. What assurances do I have that this will not happen?

If this is message is going to the wrong place, I apologise, and kindly ask you to forward it to the correct person.

Best regards,

Ben Griffin
Author, Obyx