I think that the main use for rank and unrank is to have an arbitrary, but deterministic total order on the elements, and to be able to create elements at random.
Let me also point out that this is for *enumerated* sets, which means there is a special total order on the objects. So I might not call it arbitrary. However, that is somewhat of a digression. Best, Travis -- You received this message because you are subscribed to the Google Groups "sage-devel" group. To unsubscribe from this group and stop receiving emails from it, send an email to sage-devel+unsubscr...@googlegroups.com. To view this discussion visit https://groups.google.com/d/msgid/sage-devel/0de55707-7ff1-467d-8787-5fefe2de7047n%40googlegroups.com.
