STC in VOTable: Time utypes

[Arnold Rots]

Gerard,

I have no great love for substitution groups myself; anyone who has
implemented themcarries the battle scars.
But finding an alternative that is effective is a project for STC version 2.
At this point we are trying to find a way to express version 1 in utypes,
and that means having to deal with substitution groups.

Cheers,

  - Arnold

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Arnold H. Rots                                Chandra X-ray Science Center
Smithsonian Astrophysical Observatory                tel:  +1 617 496 7701
60 Garden Street, MS 67                              fax:  +1 617 495 7356
Cambridge, MA 02138                             arots at head.cfa.harvard.edu
USA                                     http://hea-www.harvard.edu/~arots/
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