Re: What justification for separately encoding two forms of lowercase sigma

From: Doug Ewell (
Date: Sun Aug 23 2009 - 14:40:33 CDT

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    Apostolos Syropoulos wrote:

    >> Now are these two symbols not just two different ways of writing the
    >> same character? If yes, how can they be separately encoded? Is it
    >> only to keep compatibility with some earlier standard? Or can these
    >> two actually be considered as two different characters?
    > They are different characters encoding the same letter. In fact, this
    > quite common in Arabic where letter have different forms depending on
    > their position in a word.

    There is a big difference, though: the Arabic presentational forms are
    not recommended for composing Arabic text, whereas the two Greek sigmas
    are recommended, and in fact are the only way to represent the two
    "presentational forms" of sigma.

    To answer Shriramana Sharma's initial question, the two sigmas are
    encoded in Unicode for compatibility -- not only with pre-existing
    standards, but with overwhelming and widespread usage in Greek
    computing. There is only one character of this type in Modern Greek.

    Doug Ewell  *  Thornton, Colorado, USA  *  RFC 4645  *  UTN #14  ˆ

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