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

From: Hans Aberg (
Date: Sat Mar 11 2006 - 01:54:41 CST

  • Next message: Michael Everson: "OT: Middle French plural sought"

    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

    This archive was generated by hypermail 2.1.5 : Sat Mar 11 2006 - 01:56:57 CST