Esszett, Final Sigma, ZWJ and ZWNJ

[Vint Cerf]

Folks,

My reading of the consensus is that the WG has discussed and generally  
accepted that Esszett, Final Sigma, ZWJ and ZWNJ can be made PVALID.  
For registries that formerly mapped Esszett or Final Sigma, the  
solutions are:

1. block registration of Esszett and Final Sigma at the registry level  
(in which case any former registration forms are still valid but will  
not be found by entering the newly PVALID characters)

2. Bundle Esszett with "ss" and Final Sigma with lower case ("sigma")  
(and do so retrospectively for all prior registrations of the mapped  
forms).

With regard to ZWJ and ZWNJ, these would be PVALID but constrained by  
CONTEXTJ rules as to their valid usage.

As I read the charter, the WG has the latitude to adopt these  
recommendations.

It has been pointed out that there are consequences of not mapping  
characters per IDNA2003. One example relates to the appearance of,  
e.g., Esszett in a URL. A side-effect of the mapping under IDNA2003 is  
that the Esszett character would be converted to "ss" and this would  
match a registration of a domain name that contained Esszett since the  
registered form would have been mapped prior to registration into the  
"ss" form. It seems beneficial to articulate to the best of our  
ability such side-effects as an aid to users, software writers,  
registries and registrars who may need to define policies for  
registration limitations or adopt other compensating practices.

Vint


Vint Cerf
Google
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vint at google.com