"Bengt Richter" <[EMAIL PROTECTED]> wrote in message news:[EMAIL PROTECTED] > Yes, the roster model works for me too, but I'm not sure I understand > your > concept of "container/room" ;-)
I only meant that if collective objects were containers of objects like rooms are containers of people, then an object could be in only 1 collective at a time. But that is importantly not true. Therefore collectives are not containers. I once mistakenly thought of mathematical sets as being like boxes. Don't know if someone else said so or if I just thought up that error on my own. But then I realized that the box model leads to the the same counterfactual conclusion. Therefore 'box' is a bad metaphor. Sets are rosters. The very term 'member of' is a clue that I missed for years ;-) I hope to help other avoid the same mistake. The roster idea also explains how a set can be a 'member' of itself, and how a list can include itself. Weird, perhaps, but easily possible. The underlying problem is that 'contains' has two meanings: a room contains people by actual presence and hence is a container. A club roster metaphorically contains people by name (reference) as members, but not actually, and hence is not a container even though we may speak of it as 'containing'. Terry J. Reedy -- http://mail.python.org/mailman/listinfo/python-list
