Re: Question regarding U+00A6 BROKEN BAR

From: Jukka K. Korpela (jkorpela@cs.tut.fi)
Date: Thu Dec 20 2007 - 11:59:56 CST

  • Next message: Jukka K. Korpela: "Re: Question regarding U+00A6 BROKEN BAR"

    Karl Pentzlin wrote:

    > Has it other use than for mathematical logic (especially in Spain)?'

    None that I know of, except as the visual indicator of an "optional
    hyphen" in the "Show hidden" mode in Microsoft Word. So I have a few
    times used it in text when writing something like "you will see optional
    hyphens as '¬' characters".

    > Was there any specific reason to include it in ISO 8895-1 as one of
    > three mathematical symbols besides U+00D7 MULTIPLICATION SIGN and
    > U+00F7 DIVISION SIGN?

    It's not really even mathematical but logical. Robert Bringhurst's book
    "The Elements of Typographic Style" (which exhibits good, but not
    perfect, understanding of Unicode), comments that the not sign is
    useless without the other logical operators, like the symbols for "and"
    and "or", and indeed the not sign looks like an oddity in ISO 8859-1 and
    relatives. (Several other ISO 8859 codes also have the not sign in
    position AC, but many of them have taken the position to some better
    use, mostly for some accented letter.)

    But I think there might be an explanation. When the reverse solidus
    (backslash) "\" was invented, one of the reasons was that it could be
    used together with the solidus (slash) "/" to create two-character
    symbols for "and" and "or", namely "/\" and "\/"; see
    http://www.cs.tut.fi/~jkorpela/latin1/ascii-hist.html#5C
    So one might think that using these notations and the not sign, you
    could present the most elementary formulas of sentential logic. Of
    course, this is ancient history now.

    Jukka K. Korpela ("Yucca")
    http://www.cs.tut.fi/~jkorpela/



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