RE: Proposed simplification of datatype expressions

>  > From: pat hayes []
>>  >"people who have at least three values for property x."
>>  >
>>  >where x is a data valued property. I, too, struggle to think
>>  of an example
>>  >where one would actually want to use such a construct (but am open to
>>  >suggestion)....
>>  People who own three or more homes, people with at least three
>>  sources of income, people with at least three children, people with
>>  with at least three nationalities, people who have travelled to more
>>  than three foreign nations during the last six months,....
>All good examples of cardinality contraints to objects; I have to say
>that I'm not convinced that any of the following are naturally
>- homes
>- sources of income
>- children
>- nationalities
>- travel to a given nation during a date range
>Nationality, in my view, comes closest; but why is this better as a
>datatype than an object?

I have no idea; but if someone has, I see no reason to forbid them 
from saying what they want to say. I guess you have stronger 
intuitions than I do about what characterizes a datatype. I see no 
reason why any of these might not be datatypes for some purposes. 
But for a more plausible example, how about people with three 
distinct social security numbers, or events which recur on at least 
three dates, or people who have entered the country at least three 
times (identified by the date and time of entry) during a certain 

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Received on Thursday, 3 April 2003 11:28:34 UTC