Inverse of ± ?

[Dr J R Stockton]

Unicode U+00B1 is ± - a plus sign sitting on top of a minus sign,
possibly visible as "±"; "plus/minus", in ISO-7 coding.

As Alan will no doubt remember, algebraic work requiring that character
may well have need of its reciprocal, "minus/plus", a minus sign sitting
on top of a plus sign.

I've not found it in a middle-size list of Unicode characters; nor have
I found an entity name that works.

Is minus/plus, as such, in Unicode (and is it well-known to browsers)?
Otherwise, is there some alien character of the same appearance?

If not, can the omission be rectified?

--
(c) John Stockton, Surrey, UK. ?@merlyn.demon. co.uk Turnpike v6.05 IE 6
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[Harlan Messinger]

Dr J R Stockton wrote:

>
Unicode U+00B1 is &plusmn; - a plus sign sitting on top of a minus sign,
possibly visible as "±"; "plus/minus", in ISO-7 coding.

As Alan will no doubt remember, algebraic work requiring that character
may well have need of its reciprocal, "minus/plus", a minus sign sitting
on top of a plus sign.

I've not found it in a middle-size list of Unicode characters; nor have
I found an entity name that works.

Is minus/plus, as such, in Unicode (and is it well-known to browsers)?
Otherwise, is there some alien character of the same appearance?

If not, can the omission be rectified?

U+2213 = ∓

[Michael Winter]

Dr J R Stockton wrote:

Unicode U+00B1 is &plusmn; - a plus sign sitting on top of a minus
sign, possibly visible as "±"; "plus/minus", in ISO-7 coding.

U+2213 MINUS-OR-PLUS SIGN

[snip]

I've not found it in a middle-size list of Unicode characters; nor
have I found an entity name that works.

You can find it in the Mathematical Operators portion of the Unicode
code charts.

PDF: <http://www.unicode.org/charts/PDF/U2200.pdf>

It's also referenced in the General Punctuation section alongside U+00B1
PLUS-MINUS SIGN.

PDF: <http://www.unicode.org/charts/PDF/U2000.pdf>

Is minus/plus, as such, in Unicode (and is it well-known to
browsers)?

With regard to browsers, it isn't rendered (here) in MSIE prior to
version 7, though it is in Opera 7+ and Mozilla 1.0+. Perhaps this is
because those earlier IE versions are stand-alone - that tends to
introduce many annoying problems. Someone else will have to tell you if
it's a real flaw (though you have IE6 now, don't you?)

[snip]

Mike

[Dr J R Stockton]

In message <4s************ @mid.individual .net>, Thu, 16 Nov 2006
13:31:39, Harlan Messinger <hm************ *******@comcast .netwrites

>Dr J R Stockton wrote:

> Unicode U+00B1 is &plusmn; - a plus sign sitting on top of a minus
sign, possibly visible as "±"; "plus/minus", in ISO-7 coding.
As Alan will no doubt remember, algebraic work requiring that
character may well have need of its reciprocal, "minus/plus", a minus
sign sitting on top of a plus sign.
I've not found it in a middle-size list of Unicode characters; nor
have I found an entity name that works.
Is minus/plus, as such, in Unicode (and is it well-known to
browsers)? Otherwise, is there some alien character of the same
appearance?
If not, can the omission be rectified?

U+2213 = ∓

Thanks. But it's not known to XP sp2 IE6. Noted for future use.

--
(c) John Stockton, Surrey, UK. ?@merlyn.demon. co.uk Turnpike v6.05 IE 6.
Web <URL:http://www.merlyn.demo n.co.uk/- w. FAQish topics, links, acronyms
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[Andreas Prilop]

On Thu, 16 Nov 2006, Dr J R Stockton wrote:

>Dr J R Stockton wrote:

>>Unicode U+00B1 is &plusmn; - a plus sign sitting on top of a minus
sign, possibly visible as "±"; "plus/minus", in ISO-7 coding.

What is "ISO-7 coding"?

>U+2213 = ∓

Thanks. But it's not known to XP sp2 IE6. Noted for future use.

Of course ∓ is "known" to Internet Explorer 6.
But you need also a font that actually contains this symbol.
http://www.alanwood.net/unicode/math...operators.html

[Dr J R Stockton]

In message <Pu************ *****@text.news .blueyonder.co. uk>, Thu, 16 Nov
2006 18:55:43, Michael Winter <m.******@bluey onder.co.ukwrit es

>Dr J R Stockton wrote:

>Unicode U+00B1 is &plusmn; - a plus sign sitting on top of a minus
sign, possibly visible as "±"; "plus/minus", in ISO-7 coding.

U+2213 MINUS-OR-PLUS SIGN

It is now in the "characters I'd like to use" section of my local home
page - at least until it appears, I will not use it.

>You can find it in the Mathematical Operators portion of the Unicode
code charts.

HTML pages are more convincing for showing what actually works in HTML.

Someone else will have to tell you if it's a real flaw

Lack of it is a real flaw, and always has been. It was originally less
important than many other flaws --- but using "-±" is inelegant.

(though you have IE6 now, don't you?)

Yes, and alas no longer an installed IE4. So I've removed from my pages
all use of Symbol font for strange characters, except where writing
about them; and have removed for most characters the use of &#nnn; where
the entity name is now available.
It's a good idea to read the newsgroup and its FAQ. See below.

--
(c) John Stockton, Surrey, UK. ?@merlyn.demon. co.uk Turnpike v6.05 IE 6
<URL:http://www.jibbering.c om/faq/ Old RC FAQ of news:comp.lang. javascript
<URL:http://www.merlyn.demo n.co.uk/js-index.htmjscr maths, dates, sources.
<URL:http://www.merlyn.demo n.co.uk/TP/BP/Delphi/jscr/&c, FAQ items, links.

[VK]

Dr J R Stockton wrote:

Lack of it is a real flaw, and always has been. It was originally less
important than many other flaws --- but using "-±" is inelegant.

Developers had to emulate math simbols long before any Unicode, MathML
and stuff. There is a rather extensive set of tricks to represent some
parts of math notation in HTML. For your case the simplest and the
oldest one is <u>+</u>
For Strict schema you can use styled span instead:
....
..plusMinus {
text-decoration: underline;
}
....
<span class="plusMinu s">+</span>
....
Using modern CSS tools you can further reach any desired level of
emulation.

[Dr J R Stockton]

In message
<Pi************ *************** **********@s5b0 04.rrzn.uni-hannover.de>,
Fri, 17 Nov 2006 15:33:54, Andreas Prilop
<nh******@rrz n-user.uni-hannover.dewrit es

>On Thu, 16 Nov 2006, Dr J R Stockton wrote:

>>Dr J R Stockton wrote:
Unicode U+00B1 is &plusmn; - a plus sign sitting on top of a minus
sign, possibly visible as "±"; "plus/minus", in ISO-7 coding.

What is "ISO-7 coding"?

Perhaps you are too young to remember.

Once upon a time, there was a standard or set of (non-American)
standards for a 7-bit character set rather like ASCII - in fact, I
suspect ISO-7-US was the same as ASCII. There were differences around
the "Shift-3" and "Shift-4" positions, /inter alia/ providing the
generalised currency symbol which is now &curren; = U+00A4 - a circle
with an opaque centre overlaying a St Andrew's Cross.

I had a printed copy of either all "ISO-7-AllPlaces" or of ISO-7-UK +
ISO-7.

In practice, if one uses the non-varying part of ISO-7 (a large subset
of ASCII) then all systems which show it as readable text will show the
same characters with only styling variations, however configured.

>>U+2213 = ∓

Thanks. But it's not known to XP sp2 IE6. Noted for future use.

Of course ∓ is "known" to Internet Explorer 6.
But you need also a font that actually contains this symbol.
http://www.alanwood.net/unicode/math...operators.html

Well, it's not only me that wants it; my readers would need it too. If
it does not show in the default proportional & fixed-pitch fonts both
here (XP sp2 IE6) and in the Library (Win 2000?), then it's not usable.

--
(c) John Stockton, Surrey, UK. ?@merlyn.demon. co.uk DOS 3.3, 6.20 ; WinXP.
Web <URL:http://www.merlyn.demo n.co.uk/- FAQqish topics, acronyms & links.
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My DOS <URL:http://www.merlyn.demo n.co.uk/batfiles.htm- also batprogs.htm.

[David E. Ross]

Dr J R Stockton wrote:

>
Unicode U+00B1 is &plusmn; - a plus sign sitting on top of a minus sign,
possibly visible as "±"; "plus/minus", in ISO-7 coding.

As Alan will no doubt remember, algebraic work requiring that character
may well have need of its reciprocal, "minus/plus", a minus sign sitting
on top of a plus sign.

I've not found it in a middle-size list of Unicode characters; nor have
I found an entity name that works.

Is minus/plus, as such, in Unicode (and is it well-known to browsers)?
Otherwise, is there some alien character of the same appearance?

If not, can the omission be rectified?

I have a font named cmsy10.ttf that contains the minus-plus symbol.
Using escape sequences (alt-0nnn), it's at alt-0168. Plus-minus is at
alt-0167. These escape sequences, of course, are not in compliance with
the W3C specifications.

I don't know where I got this font. It's with several others named
cmex10.ttf, cmmi10.ttf, and cmr10.ttf. While I have these, they are not
"installed" .

--

David E. Ross
<http://www.rossde.com/>

I use SeaMonkey as my Web browser because I want
a browser that complies with Web standards. See
<http://www.mozilla.org/projects/seamonkey/>.

[Stan Brown]

Fri, 17 Nov 2006 13:21:48 +0000 from Dr J R Stockton
<jr*@merlyn.dem on.co.uk>:

In message <Pu************ *****@text.news .blueyonder.co. uk>, Thu, 16 Nov
2006 18:55:43, Michael Winter <m.******@bluey onder.co.ukwrit es

You can find it in the Mathematical Operators portion of the Unicode
code charts.

HTML pages are more convincing for showing what actually works in HTML.

Not really. They're more convincing for showing what works on your
browser, on your operating system, with your screen size and window
size, with your particular set of installed fonts, ...

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