```Simon Grant wrote:

> Could we agree that it would be better to limit the scope of this
> specification to represent concepts where there is indeed a consensus,
> and preferably a prior consensus, about the concepts of vagueness and
> uncertainty that we are trying to represent?

Sure!

> My suggestion remains that we try to represent clearly two concepts that
> seem completely clear to me, at least:
> 1. a range of values;
> 2. one of a range of values.

Yes, but I don't see a true reason for not clarifying the other concepts
too. You should clarify what "value" and "range" means in each case - a
"value" can be a kind of many different things!

> I think we could map most of the cases of vagueness or uncertainty onto
> one of these two, particularly if we allow (as we seem to be happy
> enough with allowing) a range of values itself to start and/or end with
> a range. Interestingly, the start or end ranges are, strictly, the
> second type of construct. Logically, a range must start and end with a
> single value (even if this is not known for sure).

> For clarity's sake, could anyone who thinks there is a really clear
> concept that is not 1 or 2 above clarify exactly what it is, and how it
> differs from the other similar concepts?

There could be:

3. A combination (set) of values. This could be different from a range,
for instance if {2000-12,2000} is the set of the month December 2000 and
the year 2000, which is not the same as the year 2000.

4. An approximate value. Approximation is a flag that marks a value
independent from other properties. The concept is based on fuzzy set
theory. For instance the approximate year 2000~ is not equal to any
strict interval.

5. a value that is questionable

As said above, in each case you need to define independently what
"value" means.

Jakob

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