Re: Temporal database - no end date

>> That sounds more useful. Can you please present these reasons? And don't just say "Zeno". <<

Actually, Zeno and (much) later Einstein are a good place to start with what happens when you think of chronons and infinity-as-process like the ancient Greeks (and the rest of the world until Cantor) did.

If I wanted to explain irrational numbers to an ancient Greek, I would use the classic sqrt(2) example and show there is at least one number which cannot be modeled as (i/j) where i and j are integers --rationals. The myth is that the Pythagoreans would kill me to prevent my telling anyone, but I am not sure if that is true or not.

So, I want a chronon model made up of not integer time points, but irrational ones.. Or transcendental or any other infinite set contained in the continuum which is not rational -- a kind of Cantor dust. Zeno proved that they had to exist, even though he did not know such concepts, because things move thru them. This is basic senior Math major stuff!

>>This is still just hand waving. Show us the simple logic instead of talking about science fiction.<<

That is the best idea you have had!!

When you said "talking about science fiction" I thought of several SF short stories and novels which are based on Chronon problems!! Theodore Sturgeon's classic "Yesterday was Monday" is based on a guy who find that today is Wednesday, but yesterday was Monday and he watches the gremlins set up the world, which is a stage (made into a New Twilight Zone episode). Only possible with a Chronon model!

 The Dayworld Series by Philip Jose Farmer in which a dystopia assigns people one day of the week to live and freezes the other six days -- daytrippers cheat and live in seven different cultures separated by Chronons of one week space one day apart.

Any number of stories where the hero can change his grandularity of time so the rest of the world is standing still. I thnk the name of the old Twilight Zone episode was "stopwatch", but I am not sure.

This is a great idea for a feature article and I will work on it when I get back from the Caribbean at the end of the month. I can probably place it in DR DOBBS -- it is geeky, mathy, and has good visuals. Perfect! Then I can use it in the next book. I might give credit, but I don't share money.

>> So what? Straw man. List is a type generator (sort of) in Java; Interval is a type generator in Date, Darwen and Lorentzo's (DDL) model. <<

Explain "sort of" in relational terms. We have base types and domains built on them in RDBMS. You are still thining in OO terms of some kind. You could say that chronons are an aleph null subset of the temporal continuum, but them you get into all of Cantor's problems. But the way Date defined it in their book, the Chronons **are** the base data type. With a continuum, we all start with a common base data type with infinite granularity and no origin (the implementations are different of course, but the base data type is the same); with Chronons, we have no common granularity or origin for the scale.

>> Is your best, most "logical" argument against the use of intervals over salesman numbers that it "feels weird"? And don't give me the crap about them not being a continuum; <<

While it might feel that salesmen are an uncountable infinite continuum when they call you on the phone, they are discrete. There really is no such as salesman #pi while there is such a moment as pi seconds after this hour. Did you see Harry Potter movie with the fractional train track?

You don't really think that discrete salesmen and the time continuum are structurally alike, do you??

Go to the Date book; look at the notation on page 122 for example. We have suppliers, parts and dates. The parts are expressed the same way as the dates -- (s1, [p1:p3], [d01:d04]) is the first row in figure 8.1. Is there a part with tag number
"p1.4142135623730950488016887242097" as implied by the notation? But there **is** a similar point in time
"d01.4142135623730950488016887242097" that occurred.

My first Masters was in Math; trust me this is not crap. BTW, what is your background? It will help me talk to you. Several years ago, I tried to explain that addition (binary, sequential, etc.) lead to series and sequences and that it was not the same as generalized summation (set-oriented). He has never had a good set theory or foundations class in college and just did not "get it" -- it was like talking to the Pythagoreans about anything more abstract than rational numbers. Received on Fri Jan 19 2007 - 02:56:44 CET