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This question was put on hold five days ago:

Is using the twin sieve to find all primes numbers better than the sieve of Eratosthenes?

After that I edited the question and tried to resolve all problems from the comments. I also highlighted the question, why was it closed?

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    $\begingroup$ It sure beats me. Yous asked a clear question. $\endgroup$ – José Carlos Santos Jul 15 '17 at 14:44
  • $\begingroup$ I'm not clear what is meant by "the twin sieve". Possibly you have in mind a variant of Eratosthenes prime sieve in which two prime moduli are sieved together. You've asked about the advantage of doing this, but your question statement is pretty far down in the post. If you are clear about what is being asked, I hope you will revise and reformat the post to make it clearer to us Readers. $\endgroup$ – hardmath Jul 15 '17 at 15:19
  • $\begingroup$ Would it be clearer what I mean if I change "the twin sieve" to "this twin sieve" ? $\endgroup$ – pietfermat Jul 15 '17 at 15:34
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    $\begingroup$ I googled "twin sieve" and the only relevant link I found was a link to your question. After reading your question, I understand what you meant, but I am sort of lazy; I would rather that you just told me what you meant at the beginning. Otherwise, I agree with @JoséCarlosSantos , it is very clear what you are asking. $\endgroup$ – steven gregory Jul 15 '17 at 16:55
  • $\begingroup$ Thanks, I will try to add an introduction. Google finds more results for me, even one other in the forum: math.stackexchange.com/questions/1664722/twin-prime-sieve $\endgroup$ – pietfermat Jul 15 '17 at 17:06
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    $\begingroup$ You can post on the Requests for Reopen & Undeletion Votes thread. $\endgroup$ – André 3000 Jul 15 '17 at 17:30
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    $\begingroup$ Regarding the link to the previous Math.SE Question, it concerns Brun's sieve for twin primes, something altogether different (for the sake of comparing efficiency, etc.) from Eratosthenes sieve (for primes). If you are sieving for twin primes, I did not get that from your Question. $\endgroup$ – hardmath Jul 15 '17 at 20:11
  • $\begingroup$ The question is deleted. I edited the question after it was put on hold. After that I got no notice or new comments. It was closed yesterday but it was not explained why, so I asked here and it got deleted today. Not something I would call ample time. $\endgroup$ – pietfermat Jul 16 '17 at 17:19
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Ultimately, I think the post has two serious problems:

  • You don't have any sort of introduction or conclusion — the reader has to skip to the middle of a long post and pick out the highlighted question to have any clue what the point of anything is
  • All of the descriptions are very terse — while they may be adequate reminders for someone who already knows what this post is trying to say, it would take someone who doesn't a lot of work to decipher what is being done and why.

Also, the mention of twin primes is a problem; to a reader who is still trying to figure out what the point of everything is, that comment appears in a place (and with emphasis) where one might expect some sort of conclusion, and thus be thoroughly mislead.

I know I definitely wouldn't have bothered trying to figure anything out if I didn't already know the trick of sieving $6n \pm 1$ (or more generally of wheel factorization), so all I had to do is confirm that you were talking about something I already knew.


There's a reason that mathematicians are still expected to take writing courses; many of the guidelines on how to write essays apply to mathematics. For example, the importance of introductions — explanations of what will follow so the reader knows what to expect.

For example:

  • Find a way to phrase your question so that it can be mentioned at the very beginning of the post before wading through the details. (it is, of course, still fine to ask again after the details, if that makes sense in the overall outline)
  • Introduce the actors in each calculation; e.g. preface the computations at the beginning with something like "Consider possible factorizations of an integer of the form $6n \pm 1$". (also, don't use $p$ if you aren't referring to a prime number)
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  • $\begingroup$ Thanks for all the tips, I will try and fix it. BTW: I'm not a mathematician and now how to write a good report. My university professor said my graduation report was the best report he ever read. It is something that is now very hard for me to do (see my profile, the tumor). I put a lot of work and effort in it but I know it's far from perfect but I have to make do with what I still can. It's has even taken me 20 years to get where I am now. en.wikipedia.org/wiki/Dysexecutive_syndrome $\endgroup$ – pietfermat Jul 16 '17 at 6:04
  • $\begingroup$ BTW: this sieve is not wheel factorization as evidenced by the Wikipedia page, other numbers are sieved. It's actually more like the Sieve of Sundaram using '6' instead of '2'. $\endgroup$ – pietfermat Aug 2 '17 at 14:00
  • $\begingroup$ @pietfermat: You sure? It really looks like you're using the basic idea of the wheel sieve (with n=6, you write down that 1 and 5 are the only numbers relatively prime to 6, then you sieve the sets $1 \bmod 6$ and $5 \bmod 6$), and have just written down explicit formulas for executing it.. $\endgroup$ – user14972 Aug 2 '17 at 14:21
  • $\begingroup$ Yes, I am sure it is similar to the Sieve of Sundaram. $\endgroup$ – pietfermat Aug 2 '17 at 15:08

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