Standardizing on IDNA 2003 in the URL Standard

Gannon Dick gannon_dick at
Fri Jan 17 20:03:10 CET 2014

FWIW Björn,

Civil Time is injective, Watches are injective, Sun Dials are not.  A quarter day is 6 hours, a half day 12.  The American Workday is 1/3 of a day with a weekend (two days off).  This is a forward looking solution.  It only works until the next Leap Day.
If you want steady state (Noon to Noon or Midnight to Midnight) ...
Start Year = Julian Day + .5 on (YEAR-1)-12-31
End Year = Julian Day + .5 on (Year+1)-01-01
The "correction" to (reversible) periodic motion is good for 16 digits.

Otherwise you are accumulating Atmospheric Refraction going forward and have no way to subtract it out going in the reverse direction.

On Fri, 1/17/14, Bjoern Hoehrmann <derhoermi at> wrote:

 Subject: Re: Standardizing on IDNA 2003 in the URL Standard
 To: "Andrew Sullivan" <ajs at>
 Cc: "Anne van Kesteren" <annevk at>, "John C Klensin" <klensin at>, "PUBLIC-IRI at W3.ORG" <public-iri at>, "uri at" <uri at>, "IDNA update work" <idna-update at>, "" <www-tag at>
 Date: Friday, January 17, 2014, 10:11 AM
 * Andrew Sullivan
 >On Fri, Jan 17, 2014 at 02:23:44PM +0100,
 Anne van Kesteren wrote:
 >> What's important for
 interoperability in domain names is translation
 >> of a sequence of code points to a
 sequence of bytes that can be used
 within the DNS.
 >This is part of where we disagree.  What
 is important for
 >interoperability is not
 only what you say, but also a reversible
 >translation so that when you get the octets
 used in the DNS back, they
 >can always be
 turned back into the sequence of code points you started
 >with.  IDNA2003 doesn't have that
 property, which is the reason for
 backward incompatibility.
 I read Anne as saying, for the purposes of this
 discussion, he cares
 about the definition of
 a `uint8_t* f(codepoint_t* input) { ... }`
 function and not user interface or other
 issues. There was no impli-
 cation in the
 quoted text whether he cares about `f` being injective.
 (He might have said something about this
 elsewhere, but not here).
 Björn Höhrmann · mailto:bjoern at
 Am Badedeich 7 · Telefon: +49(0)160/4415681 ·
 25899 Dagebüll · PGP Pub. KeyID: 0xA4357E78

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