I am very sad, I saw recently an interesting question, and I posted an answer. After it first disappeared, I posted it one more time. It took me more than one hour, to write a complete answer. And now, after a few hours, nothing, I don't see my answer.

This is very deceptive, and didn't encouraged me from invest time and energy to contribute to MY.

Have you an explanation please?

  • 2
    Do you not see the deleted answer? You should be able to see your own deleted answers meta.stackexchange.com/a/161195/166155
    – Double AA Mod
    Aug 5, 2018 at 14:05
  • @DoubleAA You are right, the deleted answer appears on the mobile version of the site; but not on the (Android) mobile app.
    – yO_
    Aug 5, 2018 at 16:17

2 Answers 2


Your answer was deleted. It's still visible to you (and mods and users with >10k reputation) if you go to the question on the site. (If you view the question in the mobile app you won't be able to see it, nor would anyone else, since the mobile app doesn't display deleted posts. In that case it might seem like it just "disappeared".)

As for why it was deleted: the question asked there was "In what way can the irrational and infinite number Pi be derived from the written Torah?"

As far as I can tell your answers were jokes. Joke answers are not allowed on serious questions, and not allowed at all outside of the beginning of Adar (see the Purim Torah Policy). (I see why you may have been confused about this because the other answer to that question is also somewhat of a joke. Arguably it should be deleted too.) EDIT: you seem to indicate it was not intended as a joke. I personally still don't understand how that is possible but perhaps that could be sufficient to alleviate this concern.

In addition, you don't cite "the written Torah" at all anywhere in your post so it doesn't answer the question the OP posted. Answers on Mi Yodeya need to actually answer the question, not just be related or somewhat similar.

I note that if a post is deleted, the solution is NEVER to try posting it again as if we won't notice that you have circumvented the rules. You can edit it to try and make it better applicable to the question it is on, flag it for moderator attention for undeletion, or bring it up to discuss here on Meta or in chat. Don't start a war with the community by posting things against their explicit wishes. (Someone doing too much of that may have to be suspended.)

If a mistake was made (or the community feels like it should be so) we can always undelete a post.

  • 2
    Okay, thank you for your response, but let me explain your three points. 1) No, no, NO, PLEASE, IT NEVER WAS A JOKE. This idea was a very serious one, that I had when doing my PhD in maths. If a moderator didn't reached the deep of this thought, IMHO the least courtesy would be to ask at least before wiping out one hour of work at late Motsaei Shabbos, with the hope that, maybe I was the איש who could bring this idea to the Community. 2) The Talmud cites the verse in Isaiah; while I hesitated if the challenge was only in Pentateuch, it could at least be a beginning, till someone finds the link
    – yO_
    Aug 5, 2018 at 13:39
  • 1
    ...with it (maybe I read that all the Tanach finds its roots in the Pentateuch). 3) I thought it was a bug (hence the tag in this post), because I posted the first try Erev Shabbos, when the network was low. And one more time, before wiping a post, it could be kind to contact the author before.
    – yO_
    Aug 5, 2018 at 13:43
  • I've looked over your answer now a few times and I still can't figure out how it isn't just a joke. I'd probably even upvote it were it posted to judaism.stackexchange.com/q/55251/759 (And yes, I'm familiar with complex analysis. You seem to be punning on "imaginary", mistaking line integration for exponentiation, and assuming your conclusion when you say "exp(i•x) = 1, so x = 2π". With a forced tie in to a hyperliteral read of a Gemara. Good quality stuff!)
    – Double AA Mod
    Aug 5, 2018 at 14:41
  • 1
    No, it is a serious idea. Ok currently not 100% sure it is the true neshama of the equation, but rather convinced. But before explaining further, how to contact who deleted the post, and ask him to bring it back on the original place? So our debate could benefit for future readers.
    – yO_
    Aug 5, 2018 at 15:37

It looks like you originally posted:

In some high math courses, π is defined as the number such that e^(2π•i) = 1.

But, what is exponential? The application that transforms addition into multiplication (if f : x --> e^x, f(a+b) = f(a)•f(b)).

A classical source (Talmud or Midrash) deduces from a verse of Isaiah that, leatid lavo, tsadiqim will make a great dance in the shape of a circle "around" H-m; while "showing Him" with their hand. And I once heard that, all the tsadiqim, everyone with his own personality and point of view, will understand that everyone was necessary in the Great Plan of the Universe.

So, this can say that, to approach the Unity, we need the whole circumference, in a situation where we can add our particularities to make a product. And all this along the imaginary line, because of the צלם notion.

After this was deleted, it looks like this was your second answer:

2π is generally known as the ratio of circle circumference over its radius. In some high math courses, π is more rigorously defined as the (smallest, positive real) number such that exp(2π•i) = 1. Where exp is the (complex) exponential, and i the basis of the imaginary line. Equation above even get more sense by defining exponential as power series etc.

Okay, but, now, what represents the exponential? An application that transforms additions into multiplications:

exp(a + b) = exp(a) × exp(b)

Now, the Talmud Taanis 31a says

אמר עולא ביראה אמר רבי אלעזר, עתיד הקב''ה לעשות מחול לצדיקים והוא יושב ביניהם בגן עדן וכל אחד ואחד מראה באצבעו שנאמר (ישעיה כה) ואמר כו' זה ה' קיוינו לו Oula Biraa said from Rabi Elazar: Hqb"h will make a circular danse for the righteous, and He sits between them in the Gan Eden, and every one shows ...

Once I heard an explanation as a metaphor. In this world, every one has his own neshama, personality, point of view to Hqb"h. But in the future, tsadiqim will make a circular danse, and every one will range the whole circle, every one will alternatively take all the places, and understand all the points of view. And, as a result, they will 'show' the 'center', they will apprehend and praise Hqb"h.

Okay, so we have an abstract metaphor that, when we could sum up the whole circle, and take a product, we will apprehend the Unity. And this is learned from the verse in Isaiah 25, 9. Reminds you something? Returning in mathematical notation. What sums up yielding a product? Exponential. Along the imaginary line, because it will transcend limits of this current World. And when you apply this to the Circle , you reach the Unity.

exp(i•x) = 1, so x = 2π

(And because the radius is not mentioned, seems to be taken as the simplest one: 1)

So, circumference of the unit circle is 2π. End of proof.

I wasn’t the one who deleted either one of these answers, so I can’t know for certain what the precise issue was. However, looking at these myself after the fact, I can see some problems with these that may have led to their deletion:

  • These answers are very hard to follow. It’s unclear to me in certain parts how you get from one stage to another. Your second, lengthier answer is much better in this regard, but it could be improved further.
  • Your bottom line is nice, even if I can’t figure out how you got there. That said, it seems to me that this is your own pshat. Nothing wrong with that, but it could be strengthened a bit. It seems to me that you really wanted this understanding of the Gemara in Taanis to work with the equation e^(iπ)=1. Again, your second answer is better, but it could be better still.
  • This one probably didn’t get it deleted, but the actual equation is either e^(iπ)=-1 or e^(2iπ)=1. See further at Wikipedia here.
  • Finally, and most importantly, the original question asked for a way that “the irrational and infinite number Pi be derived from the written Torah.” Your answers don’t do that at all. They get it from the oral Torah, based on a verse in the Prophets, but they don’t have a source in the Pentateuch. As such, they doesn’t answer the question, and likely this was the reason they were deleted.

I hope this helps. On behalf of the community, I’m sorry you had this experience, and I hope you decide to stay and share more of your insights here. One of the reasons that I included your posts here, besides to show you some potential problems with them, is so that you don’t have to start entirely from scratch - you can take these and modify them to try to address these concerns, rather than starting from a clean slate, if you’d like.

  • 3
    IMO the first three issues would be reasons to downvote, not reasons to delete. A wrong answer is still an answer, and an unclear answer can be improved. The last, on the other hand, would be a reason to delete, though we should try to give new users a hand. (I haven't reviewed this case.) Aug 5, 2018 at 12:45
  • Thank you first for bringing back the post, I hadn't courage to type it a third time. Yes, for the second post I took more time to explain. Okay it could be a little fun to tie this talmudical quote with this equation, but believe me the latter is so, so surprising (someone said it is a proof that Hm exists...), that I tried to find a jewish reason to it, and quickly arrived to the former etc. The various forms of the equation are all true, it is just notations (e.g the dot is just multiplication). And as said in comments below, a Tanach verse is probably a beginning for a Pentateuch allusion.
    – yO_
    Aug 5, 2018 at 14:00
  • If something was not clear, it is possible to improve the answer. However, purposely it didn't contained a heavy math course, to be more readable. The reader could fill the external holes by himself (the goal here was not to teach complex exponential...), and even because it is supposed to have a minimal mathematical background (Pi, irrational number etc).
    – yO_
    Aug 5, 2018 at 14:13

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