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<div>I understand that:</div>

<div>[:toCaseFold=s:] = [sSſ]</div>

<div>[:toCaseFold=ς:] = [σςΣ]</div>

<div> </div>

<div>But can someone explain me the following?</div>

<div>[:toCaseFold=ı:] = [ı]</div>

<div>[:toCaseFold=i:] = [iI]</div>

<div>[:toCaseFold=ß:] = []</div>

<div> </div>

<div>Why is it not:</div>

<div>[:toCaseFold=ı:] = [iIı]</div>

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<div>[:toCaseFold=i:] = [iIı]</div>

<div>[:toCaseFold=ß:] = [ßẞ]</div>
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<div>?
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<div style="margin: 0 0 10.0px 0;"><b>Gesendet:</b> Montag, 14. Dezember 2020 um 05:08 Uhr<br/>
<b>Von:</b> "Zach Lym via Unicode" <unicode@unicode.org><br/>
<b>An:</b> "Richard Wordingham" <richard.wordingham@ntlworld.com><br/>
<b>Cc:</b> "Unicode Discussion" <unicode@unicode.org><br/>
<b>Betreff:</b> Re: Normalization Generics (NFx, NFKx, NFxy)</div>

<div>> What does that quoted statement mean? I'm having a hard job working<br/>
> out what the meaning of full case folding is. I'm not having any<br/>
> doubts about the meaning of toCasefold(NFD(X)), so there is no issue<br/>
> for 'canonical caseless matching'.<br/>
<br/>
The "case folding is closed under canonical normalization" or the other part?<br/>
<br/>
Closed as in closure: <a href="https://en.wikipedia.org/wiki/Closure_(mathematics" target="_blank">https://en.wikipedia.org/wiki/Closure_(mathematics</a>)<br/>
<br/>
Refer to page 240 of the standard, Chaper 5 "Implementation<br/>
Guidelines" Section 18 "Case Mappings":<br/>
<br/>
<a href="http://www.unicode.org/versions/latest/ch05.pdf" target="_blank">http://www.unicode.org/versions/latest/ch05.pdf</a></div>
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