[math-fun] Is it me, or is math.stackexchange.com controlled by morons?
It's like any other social group --- initially, anything goes and there are no rules; but as time passes, certain patterns of behaviour become dominant, then codified by rules (possibly implicit but nevertheless progressively more rigidly enforced), and eventually any deviation is fiercely condemned. Appeal to the original aims of the group will ignored, if not pronounced treasonous. The only solution is dissolution: long live Ivan Illich and the revolution! I'm not going to ask why you wanted to spell "Exactly." with 15+ letters. But anyway how do you spell "hungry horse" with just 4 ? WFL On 6/21/19, Bill Gosper <billgosper@gmail.com> wrote:
https://math.stackexchange.com/questions/3268714/what-are-the-semiaxes-a-b-c... —Bill _______________________________________________ math-fun mailing list math-fun@mailman.xmission.com https://mailman.xmission.com/cgi-bin/mailman/listinfo/math-fun
Most of these sites have a minimum comment length, so if your comment is shorter, you need to pad it out to achieve the minimum. Tom Fred Lunnon writes:
It's like any other social group --- initially, anything goes and there are no rules; but as time passes, certain patterns of behaviour become dominant, then codified by rules (possibly implicit but nevertheless progressively more rigidly enforced), and eventually any deviation is fiercely condemned.
Appeal to the original aims of the group will ignored, if not pronounced treasonous. The only solution is dissolution: long live Ivan Illich and the revolution!
I'm not going to ask why you wanted to spell "Exactly." with 15+ letters. But anyway how do you spell "hungry horse" with just 4 ?
WFL
On 6/21/19, Bill Gosper <billgosper@gmail.com> wrote:
https://math.stackexchange.com/questions/3268714/what-are-the-semiaxes-a-b-c... —Bill
Hmmm ... "E = m c^2" wouldn't have got past these bastions of mathematical probity, then! WFL On 6/21/19, Tom Karzes <karzes@sonic.net> wrote:
Most of these sites have a minimum comment length, so if your comment is shorter, you need to pad it out to achieve the minimum.
Tom
Fred Lunnon writes:
It's like any other social group --- initially, anything goes and there are no rules; but as time passes, certain patterns of behaviour become dominant, then codified by rules (possibly implicit but nevertheless progressively more rigidly enforced), and eventually any deviation is fiercely condemned.
Appeal to the original aims of the group will ignored, if not pronounced treasonous. The only solution is dissolution: long live Ivan Illich and the revolution!
I'm not going to ask why you wanted to spell "Exactly." with 15+ letters. But anyway how do you spell "hungry horse" with just 4 ?
WFL
On 6/21/19, Bill Gosper <billgosper@gmail.com> wrote:
https://math.stackexchange.com/questions/3268714/what-are-the-semiaxes-a-b-c...
—Bill
_______________________________________________ math-fun mailing list math-fun@mailman.xmission.com https://mailman.xmission.com/cgi-bin/mailman/listinfo/math-fun
Comment length was a non-issue. I should've taken a screenshot. Five morons condemned me for being "off topic", threatening erasure in five days. Bill Dubuque's explanation of why they were grumpy with me nicely confirms that they're minimorons on a power trip. On 2019-06-21 15:11, Tom Karzes wrote:
Most of these sites have a minimum comment length, so if your comment is shorter, you need to pad it out to achieve the minimum.
Tom
Fred Lunnon writes:
It's like any other social group --- initially, anything goes and there are no rules; but as time passes, certain patterns of behaviour become dominant, then codified by rules (possibly implicit but nevertheless progressively more rigidly enforced), and eventually any deviation is fiercely condemned.
Appeal to the original aims of the group will ignored, if not pronounced treasonous. The only solution is dissolution: long live Ivan Illich and the revolution!
I'm not going to ask why you wanted to spell "Exactly." with 15+ letters. But anyway how do you spell "hungry horse" with just 4 ?
I'll bite. —rwg
WFL
On 6/21/19, Bill Gosper <billgosper@gmail.com> wrote:
https://math.stackexchange.com/questions/3268714/what-are-the-semiaxes-a-b-c...
—Bill
Perhaps the problem was the assumption that everyone speaks Mathematica. Try posing the question using standard English and standard mathematical notation. On Sat, Jun 22, 2019 at 2:48 AM rwg <rwg@ma.sdf.org> wrote:
Comment length was a non-issue. I should've taken a screenshot. Five morons condemned me for being "off topic", threatening erasure in five days. Bill Dubuque's explanation of why they were grumpy with me nicely confirms that they're minimorons on a power trip.
On 2019-06-21 15:11, Tom Karzes wrote:
Most of these sites have a minimum comment length, so if your comment is shorter, you need to pad it out to achieve the minimum.
Tom
Fred Lunnon writes:
It's like any other social group --- initially, anything goes and there are no rules; but as time passes, certain patterns of behaviour become dominant, then codified by rules (possibly implicit but nevertheless progressively more rigidly enforced), and eventually any deviation is fiercely condemned.
Appeal to the original aims of the group will ignored, if not pronounced treasonous. The only solution is dissolution: long live Ivan Illich and the revolution!
I'm not going to ask why you wanted to spell "Exactly." with 15+ letters. But anyway how do you spell "hungry horse" with just 4 ?
I'll bite. —rwg
WFL
On 6/21/19, Bill Gosper <billgosper@gmail.com> wrote:
https://math.stackexchange.com/questions/3268714/what-are-the-semiaxes-a-b-c...
—Bill
_______________________________________________ math-fun mailing list math-fun@mailman.xmission.com https://mailman.xmission.com/cgi-bin/mailman/listinfo/math-fun
On 2019-06-22 10:55, W. Edwin Clark wrote:
Perhaps the problem was the assumption that everyone speaks Mathematica. Try posing the question using standard English and standard mathematical notation. The opposite. There was zero Wolframese when they attacked: gosper.org/morons.png But they seem to have cowered before the Mathematica crucifix. --rwg
On Sat, Jun 22, 2019 at 2:48 AM rwg <rwg@ma.sdf.org> wrote:
Comment length was a non-issue. I should've taken a screenshot. Five morons condemned me for being "off topic", threatening erasure in five days. Bill Dubuque's explanation of why they were grumpy with me nicely confirms that they're minimorons on a power trip.
On 2019-06-21 15:11, Tom Karzes wrote: Most of these sites have a minimum comment length, so if your comment is shorter, you need to pad it out to achieve the minimum.
Tom
Fred Lunnon writes:
It's like any other social group --- initially, anything goes and there are no rules; but as time passes, certain patterns of behaviour become dominant, then codified by rules (possibly implicit but nevertheless progressively more rigidly enforced), and eventually any deviation is fiercely condemned.
Appeal to the original aims of the group will ignored, if not pronounced treasonous. The only solution is dissolution: long live Ivan Illich and the revolution!
I'm not going to ask why you wanted to spell "Exactly." with 15+ letters. But anyway how do you spell "hungry horse" with just 4 ? I'll bite. --rwg
WFL
On 6/21/19, Bill Gosper <billgosper@gmail.com> wrote:
https://math.stackexchange.com/questions/3268714/what-are-the-semiaxes-a-b-c... > > --Bill
What may not be clear is that the original question had no Mma code. It was much more concise, namely question title: What are the semiaxes a, b, c, of an ellipsoid question body: with girths G_{bc},G{ca},G{ab}? That was closed due to "lack of context". After Bill added some context it was reopened a few hours later. That's one of the compromises currently in place to deal with students cheating on their homework. Most are so lazy that they simply copy and paste the exercise verbatim, resulting in PSQs (Problem Statement Questions) having the same form as Bill's original version above. Math.SE is by far the largest general-level math Q&A web site (over 1.1 million questions). The community is so large and heterogeneous that there there are extremely diverse viewpoints on site charter, politics, etc. Some users don't wan't to have anything to do with a site possibly perceived as a homework mill, while others believe it is not the site's job to enforce policies of external entities. Some want to use the site to teach, while others wish to build a library of "proofs from the book". To accommodate these diverse viewpoints required negotiating many compromises on these issues. As with any virtual community, to understand the need for various policies requires spending nontrivial time in the community. What may appear "moronic" at first glance, may make better sense after one has more experience. That's not to say that there are not foolish things that occur (the gamified nature of the platform certainly sparks such). But, alas, there's currently no better site for general level math Q&A. Nothing comes even remotely close as far as I know. Note: if you peruse it now for the first time, be aware that is is much slower now that classes are out for the summer (so you won't see as large a barrage of copy-pasted homework) On Sat, Jun 22, 2019 at 1:56 PM W. Edwin Clark <wclark@mail.usf.edu> wrote:
Perhaps the problem was the assumption that everyone speaks Mathematica. Try posing the question using standard English and standard mathematical notation.
On Sat, Jun 22, 2019 at 2:48 AM rwg <rwg@ma.sdf.org> wrote:
Comment length was a non-issue. I should've taken a screenshot. Five morons condemned me for being "off topic", threatening erasure in five days. Bill Dubuque's explanation of why they were grumpy with me nicely confirms that they're minimorons on a power trip.
On 2019-06-21 15:11, Tom Karzes wrote:
Most of these sites have a minimum comment length, so if your comment is shorter, you need to pad it out to achieve the minimum.
Tom
Fred Lunnon writes:
It's like any other social group --- initially, anything goes and there are no rules; but as time passes, certain patterns of behaviour become dominant, then codified by rules (possibly implicit but nevertheless progressively more rigidly enforced), and eventually any deviation is fiercely condemned.
Appeal to the original aims of the group will ignored, if not pronounced treasonous. The only solution is dissolution: long live Ivan Illich and the revolution!
I'm not going to ask why you wanted to spell "Exactly." with 15+ letters. But anyway how do you spell "hungry horse" with just 4 ?
I'll bite. —rwg
WFL
On 6/21/19, Bill Gosper <billgosper@gmail.com> wrote:
https://math.stackexchange.com/questions/3268714/what-are-the-semiaxes-a-b-c...
—Bill
_______________________________________________ math-fun mailing list math-fun@mailman.xmission.com https://mailman.xmission.com/cgi-bin/mailman/listinfo/math-fun
_______________________________________________ math-fun mailing list math-fun@mailman.xmission.com https://mailman.xmission.com/cgi-bin/mailman/listinfo/math-fun
Has anyone solved the problem of determining the axes of an ellipsoid given the three girths? It has me intrigued. The mathematics is more interesting than the politics of math.stackexchange. -- Gene
Hi Eugene and Dan, In one sense, it is really a non-issue because we have three equations in three unknowns. In Mathematica: Girth[n_] := With[{c1c2 = {c[Mod[n, 3]], c[Mod[n+1, 3]]} }, Pi Total[c1c2] Hypergeometric2F1[-1/2, -1/2, 1, 1 - 4 (Times @@ c1c2)/(Total[c1c2])^2]] FindRoot[MapThread[ Subtract, {Girth /@ Range[3], {2 \[Pi], 2 \[Sqrt]2 EllipticE[-1], 4 EllipticE[1/2]}}], Transpose[{c /@ Range[0, 2], {1, 1, 1}}]] Out[]:= {c[0] -> 0.707107, c[1] -> 1., c[2] -> 1.} I'm sure you already know this, and can guess that your intrigue has more to do with the underlying function theory. If a "smart" solution exists, it has to get around a serious limitation that series inversion is not an operation that closes the set of D-finite functions back to itself. I'm not sure what Gosper is getting at (other than to upset S.E.), but there is another similar, somewhat easier problem in semi-classical quantum mechanics. Given a D-finite action function and a quantized action value, we would like to find the associated quantum energy value. This can be done by series inversion, but coefficients of the inverse series are not expected to have any simple p-recurrence. In this sort of situation I'm happy to accept numerical values for the quantized energy levels, and then move on to worrying about experimental spectra. I think this is a fairly common attitude in industry, but yes, I do also sometimes wonder if there is a stronger function theory that could do the inversion exactly? I'm only self-taught in maths, so maybe someone else already knows an answer to the overarching question: what "smart" techniques do we have for inverting differentiably-finite functions? Any at all? I'm only aware of the Faà di Bruno approach, which I find to be overly cumbersome. Cheers, Brad On Sun, Jun 23, 2019 at 3:27 PM Eugene Salamin via math-fun <math-fun@mailman.xmission.com> wrote:
Has anyone solved the problem of determining the axes of an ellipsoid given the three girths? It has me intrigued. The mathematics is more interesting than the politics of math.stackexchange.
-- Gene _______________________________________________ math-fun mailing list math-fun@mailman.xmission.com https://mailman.xmission.com/cgi-bin/mailman/listinfo/math-fun
On 2019-06-23 14:40, Brad Klee wrote:
Hi Eugene and Dan,
In one sense, it is really a non-issue because we have three equations in three unknowns. In Mathematica:
Girth[n_] := With[{c1c2 = {c[Mod[n, 3]], c[Mod[n+1, 3]]} }, Pi Total[c1c2] Hypergeometric2F1[-1/2, -1/2, 1, 1 - 4 (Times @@ c1c2)/(Total[c1c2])^2]]
FindRoot[MapThread[ Subtract, {Girth /@ Range[3], {2 \[Pi], 2 \[Sqrt]2 EllipticE[-1], 4 EllipticE[1/2]}}], Transpose[{c /@ Range[0, 2], {1, 1, 1}}]]
Out[]:= {c[0] -> 0.707107, c[1] -> 1., c[2] -> 1.}
I'm sure you already know this, and can guess that your intrigue has more to do with the underlying function theory. If a "smart" solution exists, it has to get around a serious limitation that series inversion is not an operation that closes the set of D-finite functions back to itself.
I'm not sure what Gosper is getting at (other than to upset S.E.),
For the record, although he didn't publish, Bill Dubuque was probably the first to find the decision procedure for q-hypergeometric summation. As for the five who jumped me: "Off topic" my asymptote. And no one seems to have noticed that the spheroidal special case that I added as appeasement is very easily solved in terms of InverseFunction@EllipticE. Years ago I posted here several trivariate series reversions for the semiaxes in the general case, and expressed surprise at the apparent absence of such a technique from the literature. —rwg
but there is another similar, somewhat easier problem in semi-classical quantum mechanics. Given a D-finite action function and a quantized action value, we would like to find the associated quantum energy value. This can be done by series inversion, but coefficients of the inverse series are not expected to have any simple p-recurrence.
In this sort of situation I'm happy to accept numerical values for the quantized energy levels, and then move on to worrying about experimental spectra. I think this is a fairly common attitude in industry, but yes, I do also sometimes wonder if there is a stronger function theory that could do the inversion exactly?
I'm only self-taught in maths, so maybe someone else already knows an answer to the overarching question: what "smart" techniques do we have for inverting differentiably-finite functions? Any at all?
I'm only aware of the Faà di Bruno approach, which I find to be overly cumbersome.
Cheers,
Brad
On Sun, Jun 23, 2019 at 3:27 PM Eugene Salamin via math-fun <math-fun@mailman.xmission.com> wrote:
Has anyone solved the problem of determining the axes of an ellipsoid given the three girths? It has me intrigued. The mathematics is more interesting than the politics of math.stackexchange.
-- Gene _______________________________________________ math-fun mailing list math-fun@mailman.xmission.com https://mailman.xmission.com/cgi-bin/mailman/listinfo/math-fun
_______________________________________________ math-fun mailing list math-fun@mailman.xmission.com https://mailman.xmission.com/cgi-bin/mailman/listinfo/math-fun
<< The mathematics is more interesting than the politics of math.stackexchange. >> Agreed; but politics has an unpleasant habit of intruding on our interests uninvited. RWG ain't the first to fall victim to this particular unforeseen consequence, and sure as eggs is eggs, he won't be the last. I thought WGD's analysis informative and convincing, as far as it goes --- and a salutary reminder of how fortunate we are to have math-fun run as smoothly as it does! No doubt most people on this list will sympathise heartily with a Q&A site attempting to avoid transformation into a free online plagiarism factory. So why do such efforts regularly and spectacularly backfire in this fashion? One factor --- difficult to combat --- is exemplified by the experience of a chess IM acquaintance who once found himself playing, for the team representing a very small country, on top board against Anatoly Karpov. He reported that the world champion just sat there, (apparently) aimlessly shunting rooks to and fro along the back rank, until it suddenly dawned on yer man that (as he put it) "his options had run out". For chess, the score line is eventually on hand to distinguish between naïve incompetence and incomprehensible superiority; however in mathematics, as in many real-life situations, a convenient discrimination algorithm is often unavailable. << As for the five who jumped me: "Off topic" my asymptote. >> Another recurrent feature --- on the face of it, much easier to fix --- is implicit segregation. When the club doorman refuses you entry on the grounds that you have the wrong sex, colour, religion, age, etc. you might well consider such discrimination unacceptable, but at least you know where you stand and can consider constructively how to resolve the situation. If he attempts to avoid confrontation by concocting some obviously irrelevant excuse, you are merely left bewildered and possibly angry. In a more straightforward world, SE would simply call a spade a spade: apologetically admit that an enquiry appeared potentially plagiaristic, before requesting supporting evidence that it was genuine (background, citations, etc). By attempting to avoid offending a small army of cheats, they manage instead to upset the very people they (presumably) want onboard. Fred Lunnon On 6/24/19, rwg <rwg@ma.sdf.org> wrote:
On 2019-06-23 14:40, Brad Klee wrote:
Hi Eugene and Dan,
In one sense, it is really a non-issue because we have three equations in three unknowns. In Mathematica:
Girth[n_] := With[{c1c2 = {c[Mod[n, 3]], c[Mod[n+1, 3]]} }, Pi Total[c1c2] Hypergeometric2F1[-1/2, -1/2, 1, 1 - 4 (Times @@ c1c2)/(Total[c1c2])^2]]
FindRoot[MapThread[ Subtract, {Girth /@ Range[3], {2 \[Pi], 2 \[Sqrt]2 EllipticE[-1], 4 EllipticE[1/2]}}], Transpose[{c /@ Range[0, 2], {1, 1, 1}}]]
Out[]:= {c[0] -> 0.707107, c[1] -> 1., c[2] -> 1.}
I'm sure you already know this, and can guess that your intrigue has more to do with the underlying function theory. If a "smart" solution exists, it has to get around a serious limitation that series inversion is not an operation that closes the set of D-finite functions back to itself.
I'm not sure what Gosper is getting at (other than to upset S.E.),
For the record, although he didn't publish, Bill Dubuque was probably the first to find the decision procedure for q-hypergeometric summation. As for the five who jumped me: "Off topic" my asymptote. And no one seems to have noticed that the spheroidal special case that I added as appeasement is very easily solved in terms of InverseFunction@EllipticE.
Years ago I posted here several trivariate series reversions for the semiaxes in the general case, and expressed surprise at the apparent absence of such a technique from the literature. —rwg
but there is another similar, somewhat easier problem in semi-classical quantum mechanics. Given a D-finite action function and a quantized action value, we would like to find the associated quantum energy value. This can be done by series inversion, but coefficients of the inverse series are not expected to have any simple p-recurrence.
In this sort of situation I'm happy to accept numerical values for the quantized energy levels, and then move on to worrying about experimental spectra. I think this is a fairly common attitude in industry, but yes, I do also sometimes wonder if there is a stronger function theory that could do the inversion exactly?
I'm only self-taught in maths, so maybe someone else already knows an answer to the overarching question: what "smart" techniques do we have for inverting differentiably-finite functions? Any at all?
I'm only aware of the Faà di Bruno approach, which I find to be overly cumbersome.
Cheers,
Brad
On Sun, Jun 23, 2019 at 3:27 PM Eugene Salamin via math-fun <math-fun@mailman.xmission.com> wrote:
Has anyone solved the problem of determining the axes of an ellipsoid given the three girths? It has me intrigued. The mathematics is more interesting than the politics of math.stackexchange.
-- Gene _______________________________________________ math-fun mailing list math-fun@mailman.xmission.com https://mailman.xmission.com/cgi-bin/mailman/listinfo/math-fun
_______________________________________________ math-fun mailing list math-fun@mailman.xmission.com https://mailman.xmission.com/cgi-bin/mailman/listinfo/math-fun
_______________________________________________ math-fun mailing list math-fun@mailman.xmission.com https://mailman.xmission.com/cgi-bin/mailman/listinfo/math-fun
Years ago I posted here several trivariate series reversions for the semiaxes in the general case, and expressed surprise at the apparent absence of such a technique from the literature.
I asked Bill to no response . . . Thread name / date, anyone ? I also tried to grep "rwg" + catch-phrase or "gosper" + catch-phrase, to no avail. (I did find something funny about a rattleback though). Do I need to give the many reasons why this is not an efficient search strategy, and not likely to produce the desired results? Isn't it more polite when making this sort of assertion to give the referencing information so that the readers don't have to waste their own time searching through thousands of email files? --Brad
Your question is now reopened after your edit. There are many Math.SE users who are fed up with students posting their homework verbatim with no effort, context, etc. so they will vote to close questions that look like that. To avoid that simply give some background, or show what you've tried, etc, i.e. distinguish it from the flood of copy-pasted homework questions. On Fri, Jun 21, 2019 at 3:51 PM Bill Gosper <billgosper@gmail.com> wrote:
https://math.stackexchange.com/questions/3268714/what-are-the-semiaxes-a-b-c... —Bill _______________________________________________ math-fun mailing list math-fun@mailman.xmission.com https://mailman.xmission.com/cgi-bin/mailman/listinfo/math-fun
participants (8)
-
Bill Dubuque -
Bill Gosper -
Brad Klee -
Eugene Salamin -
Fred Lunnon -
rwg -
Tom Karzes -
W. Edwin Clark