Normalization Generics (NFx, NFKx, NFxy)

Richard Wordingham richard.wordingham at
Sun Dec 13 18:51:56 CST 2020

On Fri, 11 Dec 2020 20:14:08 -0800
Zach Lym via Unicode <unicode at> wrote:

> > A string X is a canonical caseless match for a string Y if and only
> > if: NFD(toCasefold(NFD(X))) = NFD(toCasefold(NFD(Y)))  

> Even though
> Unicode explains that "case folding is closed under canonical
> normalization" it took me a long time to find that passage and
> convince myself that the W3C and Unicode matching algorithms are
> equivalent.

What does that quoted statement mean?  I'm having a hard job working
out what the meaning of full case folding is.  I'm not having any
doubts about the meaning of toCasefold(NFD(X)), so there is no issue
for 'canonical caseless matching'.


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