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I'm currently writing my PhD thesis, in a mathematical field in physics. I have published a handful of papers, and the thesis is going to be mostly based on these results. I assume that, even though they are published, I should be including full proofs in the thesis.

I also assume I will effectively need to rewrite these proofs, if only for copyright reasons, having surrendered some of my rights to the journals in which these papers were published, and also for self-plagiarism reasons.

Is there anything I should look out for, and are my assumptions correct?

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    It is self-plagiarism only if you do it without properly citing the original. If you check your copyright transfer agreement, it may allow you to re-use word-for-word your own writing in your thesis. So I think your objections are not reasons to re-write. Ask your advisor whether you should re-write anyway: it may be good for making it fit into the rest of the thesis, for example. – GEdgar Mar 22 '18 at 13:14
  • @GEdgar seeing as this has come up, I am not allowed a stapler thesis, so some amount of rewrite is completely necessary. However I wasn't sure about the ability to use proofs verbatim, since the structure of those is likely not to need any changing – A Simmons Mar 22 '18 at 13:16
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Regarding copyright: It depends on the agreement you signed when the papers were accepted for publication. All of the agreements I've signed stated that it was OK to include the paper in a thesis.

Regarding self-plagiarism: Talk to your advisor, but typically you include a statement in your thesis that some of the contents are taken from your papers, and include a list of those papers. Then you can include your papers (in whole or in part) without needing to rewrite them. However, unless you're doing a "stapler" or "sandwich" thesis, you'll probably need to do some rewriting just to make the story flow.

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I don't see how this is any different from using a proof published by another author in your thesis. Papers are published so that their results are cited. It would only be plagiarism if you didn't cite it appropriately. Your real question seems to be "can I include the proofs themselves in my thesis?" and it seems that the answer is yes. Think of what it would mean to re-write the proof - presumably you'd use different variables, but the logic and reasoning would follow almost exactly. If it didn't, then either it's a new proof (and therefore it isn't under copyright and may lead to another publication) or the proof would be incorrect.

I also think you are misunderstanding the point of the re-write. You state that "I'm not allowed a stapler thesis, so some amount of re-write is necessary". I disagree. Simply re-writing an entire paper and putting it into your thesis, even if you edit it for flow, doesn't really relieve you of the responsibility that you seem to have - that the results be either entirely novel or that there is a single, big result in the thesis rather than several smaller ones. If you have 5 loosely related papers and put it into a thesis, that's what we might call a "stapler thesis". If you have 5 papers that follow a logical progression from part 1 to part 5, then whether you just staple the papers together and call it a thesis or you write the thesis in 5 chapters, ensuring that the ideas/writing style flow properly, that's a different thing altogether. However, if there is a mathematical proof in one of those papers, re-writing it won't change the fact that it's already in that paper and therefore is not a novel result.

If your thesis depends so strongly on those proofs that the thesis essentially is the set of proofs, then I'd argue that unless you did that work as a PhD student you'll have a harder time convincing people that your work is worthy of a PhD - it wouldn't be novel research. If we could do that, then a well-published author could just enroll in a PhD program ever year and complete it by just submitting a thesis made up of the results from previous papers. On the other hand, if these proofs are useful, but an uninterested reader could just accept the citation and an interested reader could go and find the paper, then I think you have nothing to worry about by including them.

  • I'm surprised by this answer; I work in a field, as I assumed many do, where in order to successfully defend a PhD thesis, one must have published papers in peer-reviewed during the PhD. As a result, all of my results are previously published and the results themselves aren't going to be unique to my PhD thesis. – A Simmons Apr 10 '18 at 14:13
  • I've found in my particular case that it depends strongly on the supervisor. I personally did have published papers, but a colleague did not, and we both defended successfully. – Michael Stachowsky Apr 10 '18 at 14:20

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