I have seen several math papers which end with a statement like "After completing the research in this paper, we learned that all the results are already known." I wonder what are the situations in which such a comment is appropriate.

Such statements usually sound lazy to me, as though the author opted not to do a literature search at the outset, and after learning of previous work the author opted not to edit the paper (or withdraw it from submission for publication) beyond adding one sentence. Putting the comment at the end of the paper seems especially questionable, in that the beginning of the paper gives the reader the impression that the results are new. But I realize that mine is an extreme perspective which does not apply to all situations, and I would be interested to hear other perspectives.

  • Did you see those papers in reputable journals or low quality ones?
    – Nobody
    Apr 30, 2014 at 8:48
  • Reputable journals. Not in the top 10 in pure math, but certainly in the top 50. Apr 30, 2014 at 8:50
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    I usually see such comments in the introduction and they mostly refer to work that was completed either simultaneously or very recently.
    – Ri49
    Apr 30, 2014 at 9:17
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    I agree that such comments occur also in cases of simultaneous discovery of the same results. In those cases they are completely reasonable, so much so that it slipped my mind that such comments occur in that case. What I had in mind is the situation where the result was published at least 20 years previously. Apr 30, 2014 at 11:45

2 Answers 2


In part, I agree with you: if one finds out the result one has proven is in fact "trivial" (for various definitions of trivial), the "right" thing to do is to not bother submitting it for publication. (Though leaving it up on arXiv, for example, may be useful.)

But, here are some possible defenses:

  • In mathematics it is not always the result that matters: the journey getting you there is a big part of it. This sentiment is very well-expressed by Thurston in his essay "On Proof and Progress". Just because one has re-proven a well-known result doesn't necessarily mean that the paper is trivial! If the approach is new this can lead to better understanding. But in this case I, at least, would advertise this fact in the introduction beyond a single sentence.

  • As indicated in the comments, most of the time when I saw such a sentence it refers to fairly recent (perhaps even simultaneous) publications. Given that sometimes mathematics research takes time to complete, it is not entirely impossible that the authors genuinely started working on an open problem only to have the result solved in the mean time. And if the problem is somewhat obscure, I think the authors can be forgiven for only doing a detailed literature search before they start their research and not repeatedly doing it once every few months. In this case the language you quoted seems rather appropriate.

  • It could honestly be a case of ignorance! Suppose the same essential problem manifests in two distinct field of mathematics which have their own lingo. Then it is quite possible that even most experts in either field would not have recognized easily that the two results are the same. (The "two-way" relation above can also be a "one-way" relation, where researchers in field A generally don't know about result B in field C, while for researchers in field C the applicability of result B to problem D seems obvious.) In this case having the duplicate paper published will (a) help raise awareness that the problem has been solved and (b) perhaps even help the two fields become aware of each others' results.

  • Similarly, one may have discovered a simplified proof for a special case of a very powerful general result. While the result may be well-known, having this simplified proof in the special case maybe worthwhile, if only for pedagogy.

  • In the modern day of electronic communications this should happen less, but one should remember that in the history of mathematics there are many results which have been discovered, forgotten, and then rediscovered. And even with the advent of MathSciNet, sometimes very technical results are hard to search for: you have to know exactly the right string of keywords to discover it in the literature.

  • Thanks very much for your wise and well-thought-out answer! That's very helpful. Now that I think about it, what strikes me as somehow wrong is to wait until the end of the paper to acknowledge that the results were previously known, since that makes it too easy for readers to come away believing that the results are new. Apr 30, 2014 at 11:56
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    My 2 ct about ignorance and language: I've been in in a situation where I have been able to describe the problem I needed to solve in the vocabulary of my field, but couldn't find literature about solutions anywhere (including askig around at conferences). After solving the problem, the solution allowed/suggested different search terms, and it turned out that a different field indeed had some work on that. In another case, I learned much later that other fields use different vocabulary, unfortunately terms which already have a (different) meaning in my field... I don't think it is that seldom. Apr 30, 2014 at 15:20
  • @MichaelZieve: on that I agree with you wholeheartedly. I can understand that the authors want to talk about their own contributions first and foremost, but anywhere later than the end of the introduction section/paragraph would be too late in my opinion to acknowledge those other works. May 1, 2014 at 7:40

In life sciences this is quite common, although the cause may be different. Authors will typically use this sentence if after their paper was reviewed/accepted but before publication, a relevant paper was published. This can happen because many groups often work on similar subjects ("competing"). A lot of times it can be something that the reviewer/editor asks the authors to add.

In this scenario I think it is more justified, because the authors really could not have known about the other paper since it was not published yet. Also, revising the whole paper after it has gone through review may be a problem.

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