I wonder now and then, why this question is still open

Did Grothendieck overestimate topoi?

Usually, MO's members tend to be very strict about what is and what isn't a good question.

But why is this a good question?

D Clausen has clarified the controversial nature of the quote, regarding the content of the quote I really wonder if the OP has at least read RetS, where Grothendieck explains in detail why he thinks topos is a deep notion, and in fact a transformation of the very nature of space. It's ok If the Op doesn't agree with G's digression, but the question is not even a historical one.

Usually, we see questions of people that have not encountered an object in their research and they think that the object is unmotivated, or suggest a lack of imagination of the mathematician that creates it.

Topos theory now has a community, with international congresses and a wealth of publications and applications.

Why this question is research-level mathematics?

  • 3
    $\begingroup$ while I do think you can conclude from a closed question that it is not "research-level mathematics", I don't think the converse is true; In reference to your comment on the role of moderation: in most cases (spam is the exception) whether a question is closed or remains open is decided by the community, not by a moderator. $\endgroup$ Oct 23, 2021 at 19:37
  • $\begingroup$ I am going to edit that, my aim is not to be controversial in that point. $\endgroup$
    – user366545
    Oct 23, 2021 at 19:41
  • $\begingroup$ I'll just add that on the timeline of the post one can see whether it was in the close votes review queue and how many times. (In this specific case, it happened once.) $\endgroup$ Oct 24, 2021 at 6:14


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