Re: Temporal database - no end date

>> All of your continuum-based arguments are irrelevant to digital computers; they can't handle a continuum anyway. <<

Things like pi and e are handled in many programming languages with tokens, much like the NaN. **Symbolic** manipulations like you do on paper are just as good as computational ones!! Your mindset is limiting the computer! Think about it.

There are two ways to define a set: (1) enumeration (2) characteristic function.

This is important. Enumeration must list ALL of the values -- impossible in an infinite set. Characteristic functions must always be able to return TRUE or FALSE .. well, there are set that cannot have such functions, but ingore the graduate level math for now that puts in the 3VL that Chris Date hates so much

The half-open interval is a (2) method and the Chronons are a (1) methods. Let's say that we have one DB with a precision of days like Chris Date and another DB tha tworeks on weeks start on Monday. What do we do about Tuesday? In model (1), we freak out and say there is no such element in this domain. In model (2) we see that it falls after Monday and before Wednesday because we have a test. Received on Thu Jan 18 2007 - 23:14:13 CST