Mathworld errors

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David C. Ullrich

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Nov 19, 2004, 6:53:01 AM11/19/04
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I just got an email

From: Ed Pegg Jr <e...@wolfram.com>

inviting me to send him a list of errors on mathworld.
I haven't saved such a list, thought I'd mention this
in case anyone else has.

>Dear David Ullrich,
>
>Recently, on sci.math, you mentioned:
>
><<Well, yes - given that you're the kind of guy people might tend
>to believe, you might at least include a question mark or
>something...
>
>(Today must be your first visit to mathworld - it's really full of
>errors. I admit this is a good one.)>>
>
>If you would be so kind as to send us a list, Eric and I will be
>glad to fix them.
>
>Ed Pegg Jr
>MathWorld Associate

************************

David C. Ullrich

Karl M. Bunday

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Nov 19, 2004, 1:46:25 PM11/19/04
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David C. Ullrich wrote:

> I just got an email
>
> From: Ed Pegg Jr <e...@wolfram.com>
>
> inviting me to send him a list of errors on mathworld.
> I haven't saved such a list, thought I'd mention this
> in case anyone else has.
>
>
>>Dear David Ullrich,
>>
>>Recently, on sci.math, you mentioned:
>>
>><<Well, yes - given that you're the kind of guy people might tend
>>to believe, you might at least include a question mark or
>>something...
>>
>>(Today must be your first visit to mathworld - it's really full of
>>errors. I admit this is a good one.)>>
>>
>>If you would be so kind as to send us a list, Eric and I will be
>>glad to fix them.

This, by the way, illustrates scholarly practice in the mathematical
community. Any genuine mathematical researcher welcomes the
opportunity to correct errors, unlike some of the people in my kill file.
--
Karl M. Bunday P.O. Box 1456, Minnetonka MN 55345
Learn in Freedom (TM) http://learninfreedom.org/
remove ".de" to email

Eray Ozkural exa

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Nov 19, 2004, 5:21:01 PM11/19/04
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David C. Ullrich <ull...@math.okstate.edu> wrote in message news:<jfnrp0tnnfh6d19g0...@4ax.com>...

> I just got an email
>
> From: Ed Pegg Jr <e...@wolfram.com>
>
> inviting me to send him a list of errors on mathworld.
> I haven't saved such a list, thought I'd mention this
> in case anyone else has.

We had spotted some on theory-edge, too, but it's so hard to tell. I
believe I'd tried to convince some people to report to mathworld, but
they said the copyright terms were not good. Google is mathworld's
friend of course.

On theory-edge they must have a look at the following threads:
Metric question
t1 property
mathworld
post #9215

And probably other places as well, but these would be good places to
start. Google does not seem to index theory-edge archives for some
reason. At any rate... Hope this helps Ed.

Regards,

--
Eray Ozkural

Eray Ozkural exa

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Nov 19, 2004, 5:33:34 PM11/19/04
to
Dear David,

I've found these quotes about mathworld.

:mathworld has also blunders in basic combinatorics, etc.
...
:For instance, look at the page about permanent of a matrix.
:The closed formula for computing it is plain wrong!!!

ropestretcher wrote:
:When I mentioned that mathworld does not give a
:single example of a T1 space which does not satisfy
....

in response to my question ropestretcher spotted another typo:
> > http://mathworld.wolfram.com/UniversalSpace.html
> >
> > How can we compute minimal d?
>
> There seems to be a typo in the cited page - a metric
> on R is a certain mapping of R x R to the nonnegative
> reals, not a real number itself. In any event, it is
> unlikely that there is a minimal d in any reasonable
> sense of minimal because scaling a metric yields a
> metric.
...


There are probably other things in theory-edge. They should look
themselves on individual math/theory forums on the web. They can ask,
too. It's going to take their time, but it's probably worth it. They
can also put some bounties for errors on mathworld, in which case
they're going to see a huge list of legitimate errors in their inbox.
(Now, I claim mine with this post :P )

Regards,

--
Eray

Narasimham G.L.

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Nov 20, 2004, 1:42:16 AM11/20/04
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David C. Ullrich <ull...@math.okstate.edu> wrote in message news:<jfnrp0tnnfh6d19g0...@4ax.com>...

If Eric invited/requested NG directly by posting here reg. errors,lists...

Mitch Harris

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Nov 21, 2004, 4:42:25 AM11/21/04
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Eray Ozkural exa <exama...@gmail.com> wrote:
>
>I believe I'd tried to convince some people to report to mathworld, but
>they said the copyright terms were not good.

What do copyright terms have to do with reporting errors?

>Google is mathworld's friend of course.

How is that?

Mitch

Narasimham G.L.

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Nov 21, 2004, 3:03:57 PM11/21/04
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contd..
Two simple examples. For CornuSpiral Cesàro intrinsic equation rho =
c^2/s,c is neither shown in figure nor explained,(as origin to pole
coordinates along x- or y- ). The detail of KuenSurface endings appear
distressingly conical due to a too coarse 3D parameter choice when it
should be seem to be having a negative Gauss Curvature.

Eray Ozkural exa

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Nov 21, 2004, 9:08:06 PM11/21/04
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har...@tcs.inf.tu-dresden.de (Mitch Harris) wrote in message news:<30b681F...@uni-berlin.de>...

> Eray Ozkural exa <exama...@gmail.com> wrote:
> >
> >I believe I'd tried to convince some people to report to mathworld, but
> >they said the copyright terms were not good.
>
> What do copyright terms have to do with reporting errors?

You'll have to find those threads that I mentioned on theory-edge to
see the arguments of those people. I don't know exactly.



> >Google is mathworld's friend of course.
>
> How is that?

They can search for discussions mentioning mathworld errors.

Regards,

--
Eray Ozkural

David W. Cantrell

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Nov 29, 2004, 5:38:47 PM11/29/04
to
David C. Ullrich <ull...@math.okstate.edu> wrote:
> I just got an email
>
> From: Ed Pegg Jr <e...@wolfram.com>
>
> inviting me to send him a list of errors on mathworld.
> I haven't saved such a list, thought I'd mention this
> in case anyone else has.
>
> >Dear David Ullrich,
> >
> >Recently, on sci.math, you mentioned:
> >
> ><<Well, yes - given that you're the kind of guy people might tend
> >to believe, you might at least include a question mark or
> >something...
> >
> >(Today must be your first visit to mathworld - it's really full of
> >errors. I admit this is a good one.)>>
> >
> >If you would be so kind as to send us a list, Eric and I will be
> >glad to fix them.

I have kept lists of errors, and used to submit them to Eric every once in
a while. But it eventually became apparent to me that I could spend a
large part of my life doing nothing but correcting MathWorld errors...

As it happens, the "good one" mentioned above was on my list of errors yet
to be submitted, so that's one I can remove from the list. Just for the
heck of it, I decided to take care of the last four errors on the list
now. Well, the last one, which concerned an equation in the entry "Triangle
Wave", seems to have been taken care of already, so here are the remaining
three:

1) In <http://mathworld.wolfram.com/CardinalFunction.html>, the reference

Whittaker, J. M. "On the Cardinal Function of Interpolation Theory." Proc.
Edinburgh Math. Soc. 2, 41-46, 1927.

is slightly incorrect. (The mistake seems to have been copied from the
reference in the paper by McNamee et al.) Instead of volume 2, it should
be series 2, volume 1.

2) In <http://mathworld.wolfram.com/RadiusofCurvature.html>

absolute values are needed in the denominators.

3) In <http://mathworld.wolfram.com/CasusIrreducibilus.html>

the correct spelling is "casus irreducibilis", rather than "...lus".

[A copy of this post has been sent to Ed Pegg.]

David W. Cantrell

Narasimham G.L.

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Nov 30, 2004, 5:33:48 AM11/30/04
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DWCan...@sigmaxi.org (David W. Cantrell) wrote in message news:<24fe76d6.04112...@posting.google.com>...

> David C. Ullrich <ull...@math.okstate.edu> wrote:
> > I just got an email
> > From: Ed Pegg Jr <e...@wolfram.com>
....

> 2) In <http://mathworld.wolfram.com/RadiusofCurvature.html>

> you meant absolute values are needed in the denominators for curvature
or in the numerators for radius of curvature.. right?

David W. Cantrell

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Nov 30, 2004, 7:59:38 AM11/30/04
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math...@hotmail.com (Narasimham G.L.) wrote:
> DWCan...@sigmaxi.org (David W. Cantrell) wrote in message
> news:<24fe76d6.04112...@posting.google.com>...

> > 2) In <http://mathworld.wolfram.com/RadiusofCurvature.html>


>
> you meant absolute values are needed in the denominators for curvature
> or in the numerators for radius of curvature.. right?

No. I meant what I said: In the entry for radius of curvature, absolute
values are needed in the denominators. (Unless there's a usage which is
different from the one I'm familiar with, we want the radius of curvature
to be nonnegative always.)

I haven't looked at the entry for curvature itself.

David

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