Consensus Call on Latin Sharp S and Greek Final Sigma

Michael Everson everson at
Tue Dec 1 19:51:22 CET 2009

On 1 Dec 2009, at 04:30, Vint Cerf wrote:

> one reason for making the characters PVALID is to allow registries  
> to bundle registrations if they wish to achieve the same effect as  
> mapping, but without the mapping.

 From a character point of view I would favour this. It is simply the  
case that ß is not ss any more than þ is th or ð is dh.

On 1 Dec 2009, at 11:24, John C Klensin wrote:

> Please remember that, for many years, existing users needing ö (o- 
> umlaut in the German context) used "oe", so carrying this
> argument very far would rapidly turn into an argument against any  
> IDNs involving decorated Latin characters.


> Long after registrations involving "ö" started to be permitted, many  
> users continued to use the "oe" forms.  The mapping from one to the  
> other was never, as far as I know, embedded in code, but, from a  
> user standpoint, the situation is much the same: some strings  
> containing "oe" are interchangeable with the corresponding strings  
> with "ö" and, if both are not registered to the same entity and  
> either bundled or redirected, the user somehow needs to keep track  
> of what is registered and pick the correct name.

Quite so.

> And someone guessing the domain name for Herr Möller would have had  
> to know to guess "moeller" before IDNs were introduced and which one  
> to try now that they are available.

And now has "mœller" and "møller". :-)

> "ß" isn't a display form for "ss" any more than "ö" is a display  
> form for "oe".

John is quite correct here.

> They are different characters. One could plausibly consider them  
> display forms if "ß" could be substituted for every instance of "ss"  
> or "ö" could reasonable be substituted for every instance of "oe",  
> but that is not the case: Göthestraße is just wrong, not a display  
> variation of Goethestrasse.

And Eisstrasse might conceivably be Eisstraße, but it is certainly not  

Michael Everson *

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