Consensus Call on Latin Sharp S and Greek Final Sigma

John C Klensin klensin at
Sun Nov 29 18:35:56 CET 2009

--On Saturday, November 28, 2009 6:28 PM -0500 Vint Cerf 
<vint at> wrote:

> Should Latin Small Letter Sharp S and Greek Small Letter Final
> Sigma   be PVALID in IDNA2008 or not:
> Please Respond by choosing among the following:
> (1) Both characters should be PVALID
> (2) Both characters should be DISALLOWED
> (3) Only Latin Small Letter Sharp S should be PVALID
> (4) Only Greek Small Letter Final Sigma should be PVALID

(1) Both PVALID.

It is the right answer for the orthography of the languages 
involved; the key registries have indicated that they can deal 
with the transition if they have to (even while expressing a 
preference to not have to); Rationale already outlines some 
transition strategies; and, because a registry that don't want 
to deal with the characters is free to prohibit them as a 
registry restriction, it provides the most flexibility.


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