RE: Need help in interpreting symbol 225e (measured by)

From: Keutgen, Walter (
Date: Tue Mar 14 2006 - 07:21:23 CST

  • Next message: Hans Aberg: "Re: Need help in interpreting symbol 225e (measured by)"


    STIX quotes 'measeq' as SGML name of U+225e ( and as AMS/TeX name ( of it. Excuse me for the fuzzy term 'programming language'.

    Perhaps the CJK radical composition operators give an example how to generate such composites. Perhaps the Unicode consortium could think about extending their usage.

    Best regards


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    -----Original Message-----
    From: Hans Aberg []
    Sent: samedi, le 11 mars 2006 8:55
    To: Keutgen, Walter
    Cc: Philippe Verdy; philip chastney; "Gusztáv Jánvári";
    Subject: Re: Need help in interpreting symbol 225e (measured by)

    On 10 Mar 2006, at 21:27, Keutgen, Walter wrote:
    > Philippe is right. Because of the very formal mathematical
    > language, it is just dangerous to translate 'measured by' by the
    > common Hungarian verb for measuring.

    I leave the Hungarian translation issue to others.

    > I have searched the web. The only I have found is that in some
    > 'programming language' U+225e is represented by '\measeq'.

    Which programming language?

    > In some texts the character is called – from the typesetter point
    > of view of course – 'm over equal'. In order to keep the stress on
    > the =, one could opt for 'm equals'. If in other languages one
    > would need another letter, the symbol needs to be added to Unicode,
    > otherwise one ends up with different fonts per language. Or should
    > one then use a glyph variant selector?

    All I have found, is that it is added by the STIX committee, which
    somehow added because it appeared in some AMS/TeX file, it seems. I
    have found no mathematical contexe where it is used. And with no such
    math context, it is not possible to move further.

    > If Gusztáv has time, he could contact the mathematics societies of
    > Hungary and perhaps U.S.A.

    I doubt it will help. One needs math contexts of is usage.

    On 11 Mar 2006, at 05:15, Philippe Verdy wrote:

    > So it seems to me that U+225E is just a particular precomposed
    > symbol, chosen quite arbitrarily.


    > It is not enough to represent all actual uses, and it may even be
    > very english-centric for a very particular application or some
    > documents produced in some US universities, or discovered in a book
    > or article from a single author (or small group)...

    The composing of symbols and symbol components into what in effect is
    a new symbol is very common in pure math, and one cannot add them
    all. Perhaps some such less common combination just slipped through.

    > I think that mathematicians and physicians need a more complete set
    > of notations, not reduced to the few ones that are encoded now as
    > precomposed characters. For such notation, Unicode will not help,
    > and it will be easier to use MathML or TeX, that allow more control
    > on the final layout, and better respect of the semantics (lost by
    > the existing precomposed characters as they are not decomposable)

    This is another issue. I think one can add symbol components to a
    universal character set, so that these things become expressible in a
    text file, but the problem is that one needs to create a good theory
    for doing it, and that there are more than one way to do it. For
    example, one will have to decide between a rendering oriented
    approach, as in TeX and MathML, or a more semantic, parsing oriented
    approach, as that of compilers and computer language construction.
    The latter approach would be to preferred, but requires a great deal
    of more analysis of mathematical usage. I have a good idea of what
    components might be involved in this latter approach, as I write on a
    theorem prover, where those things appear naturally. But not even a
    good idea will be enough for this approach to be carried out fully.

       Hans Aberg

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