Wolfkiel, Joseph wrote:
> Just with reference to learning from the past, I just yesterday saw the
> parallel between the URI structure and it's lack of a symbol for "not
> populated" and the Roman Numeral numbering system and its lack of a
> zero--which held up mathematical development for centuries.
Traditional Hebrew also lacks zero, as did some other mathematical systems.
>
> Looks like we're repeating history :-> Hopefully our learning curve for
> CPE will be much shorter.
One problem with CPE is not quite the same as the lack of zero. It is
more precisely the presence of uncertainty, certain absence, and even
irrelevancy, with any of those denoted by the absence of some component
of a CPE identifier. When such is expressed in the CPE lexical system,
it prevents simple lexical comparisons of CPE identifiers. While such
absences could be considered assertions, they might better be considered
to be the absence thereof. This introduces at least ternary logic, but
the specific absence of information remains: the absent information has
multiple meanings lacking precise denotation, complicating equivalence
and similarity comparisons.
As for the subject question, I'll just point out that the "E" in CPE was
perhaps not the most fortuitous choice. Practically, UUID (e.g.,
http://en.wikipedia.org/wiki/Uuid) is one solution to the uncoordinated
creation of novel and unique identifiers. Registry can be a consequent
rather than an antecedent.
While it is possible to coin unique identifiers for all 7-tuples CPE
attempts to enumerate, I do not think that is a desirable goal.
It would be useful to enumerate all the things one can say about things
of interest (vendors, products, versions, etc.), and then be allowed to
say as many or as few things as one needs to sufficiently establish what
one is talking about. This is sometimes called a domain, or universe, of
discourse. Enumerating all valid statements one can utter in such a
domain is theoretically possible but has limited practical utility.