Re: Strange CORRESPONDS TO glyph

From: Kenneth Whistler (
Date: Mon Sep 07 1998 - 19:34:00 EDT

Markus asked:

> I find the glyph used for U+2258 CORRESPONDS TO in ISO/IEC 10646-1 (and
> I assume also Unicode) rather strange. It looks like an EQUALS SIGN with
> an INVERTED BREVE above. However, the only "corresponds to" sign that I
> have seen widely used in the mathematics literature looks roughly like
> an EQUALS SIGN with a wide CIRCUMFLEX ACCENT above it.
> This is not just my personal experience and what I have learned at high
> school and university math courses: ISO 31-11, which defines large parts
> of the common mathematical notation to be used in international
> scientific publications, also shows in item 11-5.4 a "corresponds to"
> symbol consisting of an equals sign and a circumflex accent that is as
> wide as the equals sign.
> Strangely, the U+2259 ESTIMATES glyph in ISO/IEC 10646-1 looks *much*
> closer to a real "corresponds to" sign than the glyph given with U+2258.
> I am not familiar with any "estimates" symbol, but could it be possible
> that the two glyphs for U+2258 and U+2259 have been mixed up
> accidentally in the preparation of ISO 10646-1 and Unicode 2.0?

No. And in fact if you would look at Unicode 2.0, you would see that
the glyph for U+2259 shows a more prominent (and wider) hat than that
shown in 10646. And the entry for U+2259 is:

2259 <glyph> ESTIMATES
        = corresponds to

which shows the aliasing to the sense of "corresponds to" for the
symbol you are familiar with.

The reason for the name (and the proximal source) for U+2259 is the
Xerox Character Code Standard, which contains this character at position
356B/075B with the name "Estimates or is estimated by". It is also
"/wedgeq" or "\wedgeq" or "wedgeq" in SGML, etc.

I don't know the proximal source of U+2258, but it is referred to
currently as "arceq" in the AMA's list of math symbols.


> Markus
> --
> Markus G. Kuhn, Security Group, Computer Lab, Cambridge University, UK
> email: mkuhn at, home page: <>

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