Talk:Kaplansky's theorem on projective modules: Difference between revisions

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==Comments==
I have two comments: the proof of the theorem in the article currently does not highlight the point where the assumption that the ring is local is used. This could be improved. Secondly, [[WP:NOTTEXTBOOK|WP is not a textbook]], and this article is practically an excerpt of a textbook. I think the article would gain much from rather highlighting applications of the theorem and also from [[WP:WE|not addressing the reader directly]]. [[User:Jakob.scholbach|Jakob.scholbach]] ([[User talk:Jakob.scholbach|talk]]) 08:23, 19 December 2019 (UTC)
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::OK, these steps go in the right direction, I think -- thanks! I am by no means an expert on this topic, but searching around a bit reveals for example a paper by Bass " Big projective modules are free. " where he states it relies on Kaplansky's theorem. More systematically, it may also be instructive to check out the list of papers referring to Kaplansky's paper such as this [https://mathscinet.ams.org/mathscinet/search/publications.html?revcit=100017&loc=revcit list of papers whose MR review refers to Kaplansky's paper] is also insightful, I guess. [[User:Jakob.scholbach|Jakob.scholbach]] ([[User talk:Jakob.scholbach|talk]]) 08:27, 20 December 2019 (UTC)
:::Thank you for the info about Bass's result (which I didn't know). I have added it to the article. I think, while I understand the importance of mentioning applications in general, that this theorem (as well as Bass's result) says that big (=not finitely generated) modules are somehow ''boring'' as far as the subtletysubtleties like onea distinction between free and projective modules are concerned. This is really not surprising if you remember algebraic topology: stable problems and situations tend to be easy (or equivalently boring for mathematicians). But this type of a general discussion probably belongs to the main article "[[projective module]]". -- [[User:TakuyaMurata|Taku]] ([[User talk:TakuyaMurata|talk]]) 01:54, 22 December 2019 (UTC)