@amWhy Thanks!

One more vote needed for closure: math.stackexchange.com/q/4169188

For deletion: d-i, d-ii, d-iii, d-iv, d-v, d-vi

For closure: c-i, c-ii, c-iii, c-iv

It seems that the OP of this PSQ is dumping (on-going?) contest problems on MSE.

@user21820 The score of this question is beyond absurd and far more shocking than that the answer was upvoted and (not surprisingly) has an undelete-vote. How could this question receive such a score within just a day ?

D

D

Close this low quality question

Close as low context There is a dupe target in the comments in case.

@TeresaLisbon Thanks :) voted to close as dupe

@postmortes Welcome! I was semi-relieved that no one chose to answer.

I mean... one doesn't need very many hypotheses for every subsequence of a convergent sequence to be convergent.

:\

I think all of the necessary hypotheses are in my comment above. :/

@XanderHenderson True, but this is exactly the kind of question I would have seen a less reputed user take a pop at. It's seemingly on topic with context (for them). The fact that it's a duplicate is going to escape a lot of newbies.

I hope all high rep users will have been warned enough to not be attempting that!

I read this answer of mine from more than 4 years ago It was one year after I had joined the site : I'm happy I had some alignment with site ethos (if not as much as today!) even at that time. I used to worry that I started out misaligned : maybe it wasn't the case.

@TeresaLisbon The first commentor on that question has, historically, been a very fast answerer to any question that would fit into a first course in functional analysis, but since the EoQS they've started just providing comments instead on low(er) quality questions -- which I think is a good approach to take. I suspect that their comment is enough to deter others from answering as they've have to somehow do better :)

@postmortes Correct, I didn't realize the hidden benefits of such a comment!

C1, C2, C3

@Peter Well, it's always been like this. There are always some people who seek to protect nonsense. Anyway high undeserved upvotes typically come from the HNQ.

@XanderHenderson VV = W

Y r VV, My response to tee-why.

[ SmokeDetector | MS ] Mostly non-latin body (80): Solve the problem by Adrit Nag on math.SE

This pure PSQ acquired 6 upvotes! Downvote and delete?

@XanderHenderson: What do you think of this Collatz question? Do you agree that it should be closed for being about an open problem and not having any actual value?

Seeking slightly strange personal advice.

integral psq

@vitamind You didn't vote.

@user21820 This question is strange in many ways..

@vitamind Similar question. I didn't check but I might even guess that a large part of this user's rep could have come from questions with the phrase "I have managed to boil [it] down to".

@user21820 I do hope that when they start university level mathematics they lose this intensity for the Collatz conjecture and start to appreciate the whole realm available to them

@postmortes Indeed. But I have a nagging feeling that this is not just an upcoming undergraduate student.

@user21820 I've voted to close.

Thanks.

@amWhy Yes, I understood that.

It took me a minute to figure out "our".

@XanderHenderson ;D

$z\land$er

@user21820 If it were just the first two or three paragraphs, my impression would be that there might be a reasonable question buried in there (i.e. "What exactly is the Collatz conjecture?"), though I expect that that question has already been asked. The attempted resolution takes the question way off topic.

@amWhy The question I asked was about "r" vs "our" vs "are".

@XanderHenderson r sounds like are; our sounds like hour ;P

@amWhy Right. I was suggesting "are" as an alternative to "our" (which was the original version, I think).

@XanderHenderson I meant "are": Y r w: you are welcome. I took your "tee-why" to mean TY, i.e. Thank you.

saying double-u, would have been too easy to figure out!

Ugh... text is a terrible medium of communication. Yes, I understood the meaning of "why our double-vee." It took me a while to parse what "our" was supposed to mean, so I suggested "are" as an alternative. :P

The double-vee seemed pretty clear.

@XanderHenderson Do you like my abbreviation of your current first name?

Meh. I'm pretty attached to that "x".

Yeah. I saw. I'm pretty attached to the "x", so am not overly fond of that "spelling". :\

@XanderHenderson well, I guess $x\land r$

$x{\land} er$ looks okay.

though x$\land$nder maybe reads better

But I think that xander is best.

@XanderHenderson ;-)

@vitamind I would argue that the question is a little different.

It is a question about the particular argument, not the underlying fact.

@XanderHenderson Ok that's right. But the question is imho still at the edge of "needs detail or clarity". I'm not going to vote to close it.

@vitamind I think that the question is okay. The asker seems to understand the argument, but is confused about what it means. Whether or not the question is a duplicate is another matter, but I am not finding anything right off.

@Xander I do not think this question belongs on site, because it seems to require knowledge of OPs paper submitted for publication, and understand feedback... ???

Agreed.

@amWhy It's really weird; if the author published the paper, why is the author struggling to interpret some figure in the paper?

@XanderHenderson Thanks.

@user21820 I cannot make heads or tails of it.

@vitamind If we think about whether it has lasting value to this site, I don't see why it shouldn't be closed.

@XanderHenderson It seems the OP immediately deleted the post upon it's closure. Again, Tee Ewe!

If I'd post an anwer to this question, I would look at the structure: Suppose $a=b$. We know that $a+a+a=c$. We also know that $b+b+b=d$. "Since we know that $c\neq d$, $a\neq b$". It is more than obvious that the argument $c\neq d$ is wrong.

@Xander Interestingly, scik.org/index.php/jmcs/article/view/5588, but I don't know whether that is a reputable journal or not. My Google search found it in pdf format for download, which suggests not necessarily. But the journal claims to be peer reviewed.

It is possible that the image used in the paper was relevant to that project; and since then, the OP learned the image could be understood wrt another problem, as well? Even if legit, it's way beyond the scope of this site.

interesting, but unfortunately poorly presented

@Xander I think Larry Freeman asks a fair, polite question here on meta. Personally, I am confident he is sincere. It would probably be good for the team to work on a statement regarding this conjecture. Yes, I understand that may on this site are burned out on the Collatz Conjecture, and rightfully so.

But I think the question Larry asks deserves a solid, authoritative answer. Or at least why this topic raises red flags for many users, who are skeptical, for reasons that are well founded.

@amWhy Is the question about the usual Collatz sequence (and not about some generalized version) ? If so, we can safely assume that there is no known disproof of a divergent sequence. What might be woth mentioning : A very generalized version of the Collatz conjecture was even proved to be undecidable.

I agree. I am working on vitamin d's 0.999... question right now (as I cannot find a good duplicate, and I think that there is an important definitional problem which underlies the question), but I'll have a longer look at it when I am done.

I did leave a comment.

@XanderHenderson Great! No urgency here.

@Peter math.stackexchange.com/questions/4167179/… takes you to the question Larry asked.

@XanderHenderson Is this the "contradiction proof" of $0.9999\cdots=1$ , which does however nowhere contain a wrong assumption ? I have diffuclties to understand how this should be proved by contradiction. I am only aware of direct proofs of this claim.

@amWhy Seems to be about the "usual" Collatz conjecture.

@Peter No, the claim is that the "usual" high school proof that $0.\overline{9} = 1$ is, actually, a proof by contradiction that $0.\overline{3} \ne 1/3$.

@Peter Indeed. But I think the OPs question on meta brings up a good point, that perhaps "what is appropriate on math.se/what is not, and why it is not." needs an update, or at least an authoritative/ or definitive statement of what is by definition off topic here.

D

D

@XanderHenderson I beg to differ. The OP clearly does not seem to understand that $0.999... =1$. Hence he's reached no contradiction, whether starting with .333...., or starting with .999..., it is in fact a direct proof.

@amWhy Basically it happens every time someone does not understand how to rigorously get rid of "...". Maybe we shouldn't use ellipses in teaching about real numbers, unlike in English...

@Peter Shouldn't the non-math question itself be deleted as well? I guess you mean that, right?

@user21820 Perhaps. But I don't think ellipses are to blame. The same confusion results when it is written: $0.\bar 9$.

@user21820 I delete-voted the question as well, since it is a very poorly designed paradox-attempt.

@amWhy I disagree. The fundamental problem is that the asker does not understand what ellipses mean. This is related to the 0.999 question, and the fact that they don't believe that 0.999=1 is implicit in the question, but I think that the underlying mathematical issue is distinct.

@amWhy Ah, yes, you're right. Hmm...

@XanderHenderson We'll simply have to agree to disagree.

@amWhy Fair enough.

Ellipses and $0.999\cdots =1$ ? What is the link between those things ?

@XanderHenderson They never wrote 0.999=1, ever. You're not seeing things that are there.

@amWhy They wrote 0.999...=1 several times.

I simply elided the ellipses because I am lazy.

@Peter Wrong question: repeating decimals $0.\bar 9 = 1$

@XanderHenderson As you say, it is good that the op doesn't believe 0.999=1, because it doesn't. Since you are a moderator, you can edit any comment. I stand by my second to last statement unless you correct yourself. What you wrote, and I and the OP wrote, are not the same claims.

@amWhy I am not sure why you are being so hostile to me right now.

I am sorry that I lazily wrote 0.999=1 when I meant 0.999... = 1.

I figured that we all understood the context here, and that the meaning was clear.

@XanderHenderson I am not being hostile. You're insistant, defiant, about not admitting a mistake. That's all.

@amWhy It was not a mistake. It was laziness.

I am sorry that my laziness is causing you such consternation.

Again, I made the assumption that the context made it clear what I meant.

Again, I apologize that this was not the case.

@XanderHenderson Whatever you want to call it. Tomato, tomato

@XanderHenderson Do you accept that as an excuse a student gives on a test? "I was lazy, I didn't finish what I thought was obvious. I assumed you'd know by context what I meant"?

@amWhy Yes, generally, I do. My goal on an exam is to determine whether or not my students understand the underlying concepts. If I saw something like that on an exam, I might mark off a point or two, then give that point back to any student who came to my office and explained what they meant.

Notation matters. And if that had been what the OP on that question wrote, you can damn well bet that you'd have pointed it out manifestly, in your answer.

And this isn't an exam.

This is informal communication in chat.

Why are you attacking me like this?

I mean, why isn't "Xander, the OP never said 0.999=1" "Oh, sorry, I was being lazy, I meant 0.999...=1" the end of the conversation?

Why must you continue to imply that I am lying about what I meant?

You asked for clarification, I clarified. I am not sure why you are unable to accept the explanation (or, indeed, why the explanation even matters).

@XanderHenderson Stop mis-representing my words! please don't behave in such a defensive manner. I am providing rational, and compelling arguments, and if you want resort to name calling and disparaging words, then you it would be best for you to take a time out, or refrain from escalation. I am not implying you were lying. Just careless, or as you say, lazy. But look how many times you blame for missing the context, not appreciating informality, i.e., you're trying to blame me for saying anything

If you want me out of this room, as you already previously demanded, as I remember correctly, then say so. But don't expect me to honor that request.

Of course, @Xander, I'll put on hold, particularly given your mood, any action on

@amWhy You are misreading me.

I did not expect you to understand. I made an assumption that you would understand. I have apologized repeatedly for the misunderstanding and confusion that this cuased.

Why are you still coming after me about this?

What is the outcome you want from this interaction?

@XanderHenderson One time, and how many times have you since blamed me for not understanding your assumption that I would understand. You give back-handed credit, only. The outcome I want? Stop blaming me for pointing out your errors. I get it, I make errors to, and cringe, but I get truly bothered by your incessant need to try to "save face". I am an extremely understanding person, to those not trying to throw back blame to me. What is the outcome you want from me... Because you fail to see that

you play a role in the outcome, too. Indeed, you play a bigger role.

haha :)

Yes. The error I made was laziness. I have apologized for that. I am leaving this conversation now, because I have no idea what you want from me.

@XanderHenderson No problem. If you want to storm off in a temper tantrum, go ahead. I have no problem with having been a little lazy. I do have a problem with how you have targeted me here. But I can accept that I can not expect that you'd behave like an adult, and Professional. Now I will have not expectations of you, @Xander.

@vitamind I know "Feynman's trick" only from the big bang theory. The mentioned exercise there can be solved by intgeration by parts, no Feynman-trick needed.

@Peter I can't remember :( Feynmans trick is beautiful but isn't too reliable.

@vitamind Sheldon asked Howard how he would integrate $x^2\cdot e^x$ and Howard mentioned the Feynman trick (differentiating under the integral)

Thanks, @Xander, for comments on both the meta post, and on the original post, re: the Collatz Conjecture question and meta post.

@Peter What did you expect? Howard is an engineer :)!

This question (which has an answer??!!) needs to be closed.

^^^^^ My bad. I can't fault the answerer of the above linked question, which I see was posted in 2017. But we have been tracking and closing PSQs for quite some time, so close votes are still welcome.

To those not pingable from the cafe, @RRL,@KReiser, anyone, come to the linked chat room for our current word search!

@postmortes, @an4s, @ArcticChar, @OliverDiaz, come on over to the cafe for our current word search: REPEATING DECIMALS

@Joe, @JoséCarlosSantos, @JyrkiLahtonen, @JitendraSingh please have some fun in the cafe!

^^^^^^^^ chat.stackexchange.com/rooms/112937/…

Close & Del dupe of FAQ

@BillDubuque Closed

@Bill I dv'd, but we need three more to dv in order to delete quickly. Nice call.