TITLE: proper quoting of theorems
QUESTION [5 upvotes]: Dear collegues, I am writing an overview paper for an academic journal, where I also need to state theorems proved by other authors. Usually I cite the source and then rephrase the theorem. However in a few cases rephrasing seems counterproductive and the optimal formulation was already given by the author. Is it OK to refer to the original author and then give say a 2 lines long theorem verbatim? Can this be considered as a ``weak" form of plagiarism?  Thank you for your answers.

REPLY [5 votes]: As far as I know, it is not plagiarism to use someone else's exact words as long as you make it clear that they are that other person's words and not your own.  If you do this with a long piece of text, though, it might be copyright infringement, and there I don't think either Barry's suggestions or quotation marks would help.  I think avoiding plagiarism is solely your responsibility, but avoiding copyright infringement is something you and the eventual publisher of your paper should handle together.  (Maybe I should add that I consider plagiarism a serious moral issue; copyright is primarily a legal issue with, admittedly, some connections to morality.)