Re: Sets and Lists, again

Bob Badour wrote:
> JOG wrote:
>
> > Sadly I cannot recall what combination of posts swayed me, but I now
> > appear to have a firm conviction that a 'chronological list of
> > presidents' makes no semantic sense outside of informal description. To
> > my eyes, one may have a 'set of presidents' and a 'list of
> > presidencies' (or an ordered set of presidencies if one prefers). I
> > would love to see some formal presentation of this standpoint, and I
> > would be suprised if it didn't exist, in some text, somewhere.
>
> If one has a set of presidencies, one also has a list ordered by any
> domain therein with a total order.
>
> If one has a set of presidencies, one has a set of presidents by
> projection. One likewise has a set of terms of office by projection.
>
> A list of presidencies that omits the ordering attributes might be
> useful for presentation provided one does not forget the attributes from
> which the list was ordered. Once one forgets the attributes one has no
> way of knowing whether the order means anything.

agreed. I was implicitly referring to chronological orderings, but you're correct, any ordering is valid. Received on Mon May 22 2006 - 03:02:56 CEST