On Thu, Nov 13, 2008 at 3:24 AM, Robert Bradshaw wrote: > > On the note of making it easy to understand, what would people think > of renaming Parent to SetObject or even just Set? This would clear up > the very frequently asked question "what is a Parent?" to give it a > more mathematically-grounded name. >
Although I seriously doubt that the Sage developers would agree to change the name of something quite this fundamental in Sage, since I was/am one of the people who have been most critical "parent" in Sage, it is hard to let this pass without comment. In fact we have discussed this previously in the thread: http://groups.google.com/group/sage-devel/msg/423c69d7f48dcd3d David Harvey proposed what I think is a more precise definition of "parent": >> Bill Page wrote: >>> How does it related to the concept of "parent" - which seems equally >>> ill-defined to me? > On Jun 3, 2008, at 10:04 PM, Robert Bradshaw wrote: >> A Parent is an Object in the category of Sets, David Harvey wrote: > huh? Don't you mean to say something more like "a parent is an object > of a concrete category", i.e. a category C with a faithful functor > f : C -> Set, such that the "elements" (as understood by Sage) of the > parent P are exactly the elements of f(P)? I rather like David's definition because it is careful to make a connection to category theory. Unfortunately, as far as I can tell Sage does not directly implement this notion. I mean: there is no such identifiable concrete category in Sage as such, even if it is true that a parent "behaves" in this manner. In any case, perhaps it would be helpful if 'parent' was replaced with sage: concrete_category(1) Integer Ring But there is a further complication since there already is some kind of "category" associated with elements: sage: category(1) Category of elements of Integer Ring I do not understand what this really is yet. It does not seem to me that the elements of Integer Ring actually form a category as such. Regards, Bill Page. --~--~---------~--~----~------------~-------~--~----~ To post to this group, send email to sage-devel@googlegroups.com To unsubscribe from this group, send email to [EMAIL PROTECTED] For more options, visit this group at http://groups.google.com/group/sage-devel URLs: http://www.sagemath.org -~----------~----~----~----~------~----~------~--~---
