VOUnits 1.1 RFC

[Markus Demleitner]

Dear IVOA,

On behalf of Norman (the Editor) and Baptiste (the Chair of the
Semantics WG), I invite the community and TCG to review of VOUnits
1.1 at <https://wiki.ivoa.net/twiki/bin/view/IVOA/VOUnit11RFC>.  This
is a relatively minor update touching only relatively few points.
There is no need to re-read the whole document (although you are
certainly welcome to do so):
<https://ivoa.net/documents/VOUnits/20230502/index.html>.

If you want, you can simply review the diffs at
<http://github.com/ivoa-std/VOUnits>.  Alternatively, the
in-document changelog is:

* Clarified: that Besselian year is not in FITS.
* In FITS 4.0 the preferred symbol for the year is
  \unit{a}, not \unit{yr}
* The VOUnits syntax now accepts \unit{1} as positively
  indicating a dimensionless unit string, and the text no longer
  recommends that the empty string `positively indicates that the
  corresponding quantity is dimensionless'.  An application is free
  to interpret the empty string as indicating a dimensionless
  quantity, that the units are unknown, or that this is a parsing
  error
* Added brief rationale for the syntax of the VOUFLOAT
  terminal
* Now allowing new SI prefixes r, q, R, Q.
* Document management: ported to ivoatex, streamlined use cases,
  several editorial changes.

In addition, we have left one issue open,
<https://github.com/ivoa-std/VOUnits/issues/18>; we don't *have* to
resolve it during 1.1 RFC, but it would not hurt, either.

The RFC period is 2023-07-01 – 2023-08-15; we would all appreciate
comments comming in in time.

Thanks,

         Markus