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<div class="moz-cite-prefix">On 10/29/2022 3:42 PM, Sławomir Osipiuk
wrote:<br>
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cite="mid:1667082249887.4172968439.3675259820@gmail.com">
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<span class="viv-signature"></span>On Saturday, 29 October 2022,
17:56:20 (-04:00), Asmus Freytag via Unicode wrote:<br>
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<div class="moz-cite-prefix">I can see no indication that the TI
engineers had some other symbol in mind, that is had they had
the choice of a Unicode-encoded outline font, they would have
chosen something with an appearance very distinct from
SUPERSCRIPT MINUS. Unless and until someone can come up with a
very cogent argument that they were really trying to model
something that is visually distinct from a superscript minus
sign, there is no reason to reject that mapping.</div>
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solid; padding-left: 1ex"> </blockquote>
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<div>The argument is simple enough: a minus sign as part of the
exponent should be visually distinct from a negation sign in
the base.</div>
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<p>And they are. One comes before the base, the other one after the
base. And since negation is unary, it's never preceded by anything
other than an operator, delimiter or a space.<br>
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<blockquote type="cite"
cite="mid:1667082249887.4172968439.3675259820@gmail.com">
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<div>The TI engineers were trying to visually separate
subtraction and negation. To the extent we can try to deduce
their reasoning, they would not have wanted to immediately
confuse negation with negative exponents, which is what the
superscript does.</div>
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cite="mid:1667082249887.4172968439.3675259820@gmail.com">
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<div>Someone with the appropriate calculator can confirm: What
does 3⁻¹−-3 ("three to the power of negative one, then
subtract negative three") look like? If the negative symbol in
the exponent and the one preceding the three are the same,
I'll admit the superscript is fine in this case.</div>
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<p>You don't need the calculator - you can look up the 7x5 bitmaps
for the fonts. The result looks like</p>
<p>3⁻¹−⁻3</p>
<p>which is clear and unambiguous. The second ⁻ cannot ever be part
of an exponent.</p>
<p>BTW, the same engineers have a provided a precomposed symbol for
⁻¹. The Wikipedia suggests mapping that to <207B 00B9>,
while the other source maps that to <203E 00B9> which uses
the clearly inappropriate overline.<br>
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cite="mid:1667082249887.4172968439.3675259820@gmail.com">
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<div>My view is that the modifier letter minus (U+02D7) is the
best option to respect the intended semantics, while the plain
hyphen-minus (U+002D) would be my second choice.</div>
<div><br>
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<div>As for Wikipedia, it's ridiculous to say that one person's
opinion on an extremely esoteric detail, left uncontested (or
more likely unnoticed and unquestioned) is enough to form some
kind of de facto standard. But, if we are going by that logic,
I suggest you check the page again. ;-)</div>
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<p>No more ridiculous than your personal choice, immediately
contested here. :)</p>
<p>The fact is that a centerline glyph, no matter whether shorter
than the minus sign or not, does not match the conventions used by
TI. You are, of course, free to suggest that your notation is
superior; it's just not a better *mapping* for what is available
on those calculators. However, nothing prevents you from using it
in your own documents.</p>
<p>Neither makes an argument for encoding a new characters - which
is what had started this thread.<br>
</p>
<p>A./</p>
<p>PS: incidentally, the TI font has both a "DASH" and "HYPHEN"
(names given in one of the listings for the characters). The
former has the width of what Unicode encodes as 2212 (same as the
while the latter is shorter. The location in the original set near
"+" and "=" makes clear that "DASH" is meant for the minus sign
and the mapping in both source and Wikipedia therefore has 2021
for it, while the "HYPHEN" is mapped to 2010.<br>
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