issue with non rigid classes

from Chris: "I don't think Graz is ready yet. The status of non-rigid classes is still very unclear, there needs to be more documentation here. I can discuss more on the BFO call today." from Alan: "Chris can you write up a document that explains what the issue with nonrigid classes and exactly how it impacts the work you do? If we are going to solve this issue we need a target that we agree on" thread at https://groups.google.com/forum/?hl=en&fromgroups=#!topic/obo-operations-committ ee/4ZrPc1NB7ds

I'm not sure the onus is on me to write a document (I've already brought this 
up on the bfo owl list with no resolution). I think the documentation needs to 
be on the BFO2 owl side.

The release notes are a good start, but the status of non-rigid classes are not 
clear. Let's say I want to start developing an ontology that includes classes 
such as "human with Parkinson's disease" or "infected lung". Are these 
non-rigid classes forbidden with BFO2? Can I go ahead and add them to my 
ontology, even though BFO2 owl says they are uninstantiable? Do I have 
guarantees that I will not be forced to change my model at some future date? 
And what about situations such as nucleus and cell? Do I just go ahead and use 
part_of_at_all_times and add an annotation that this is actually false? And if 
I do this do I have guarantees I will not have to change my model further down 
the line?

Original comment by cmung...@gmail.com on 26 Nov 2012 at 6:55

zhengj2007 / bfo-export

issue with non rigid classes #132