Re: Sets and Lists, again

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. Received on Mon May 22 2006 - 03:00:09 CEST