Hi, the notions "parent" and "element" are programmer's notions rather than mathematical ones. They are natural if you look through the object-oriented glasses.
Mathematically, one could build "everything" purely out of set-theory, and would have sets, power-sets, power-power-sets and their power- sets, classes and so on --- but that would not make much sense from the programmers' point of view. I think in Sage there are only "elements" and "parents" --- but not "parents of parents" and the like. Or am I mistaken here? Cheers, gsw --~--~---------~--~----~------------~-------~--~----~ To post to this group, send email to sage-devel@googlegroups.com To unsubscribe from this group, send email to sage-devel-unsubscr...@googlegroups.com For more options, visit this group at http://groups.google.com/group/sage-devel URLs: http://www.sagemath.org -~----------~----~----~----~------~----~------~--~---
