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From: Deane Yang (deane_yang_at_[hidden])
Date: 2005-10-10 22:22:24


Jeff Garland wrote:
>
> Wow, that's amazing. Replace quantity_vector with time_duration and
> quantity_point with time_point and you have the core concepts behind
> date-time. And the 32 versus zero -- seems an awful lot like an epoch_time
> adjustment. So I suppose I'm saying I believe there is something fundamental
> here :-)
>

Yes, there is.

If you dig back in the archives, I tried to explain it all before, but
obviously not very well. Suffice to say that a "time point" and a "point
quantity" are the same type of thing and that the difference between any
two such things is a "vector quantity" or equivalently a "time_duration".

Mathematicians have identified the common abstract concepts underlying
these things, and I went on and on about this earlier. But I think I'm
going to resist reviving all that, because I don't think it's
particularly helpful. I like Matt's terminology, because it seems to be
more meaningful for everyone.


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