About two weeks ago I asked this question on MSE: https://math.stackexchange.com/questions/1085946/when-should-i-be-doing-cohomology. (Short version: what are some ways I can tell that some sort of cohomology theory might be relevant to a piece of math not obviously about cohomology already?) It received some interest, but no responses even after I offered a bounty.

I posted it there because I'm fairly certain that it's too elementary for MO; on the other hand, I'm certain there are interesting things that can be said about it. So my question is,

Is the question above appropriate for MO? If not, are there ways I can modify it so it becomes appropriate?

(Of course, regardless of the answer, I'll wait until the MSE bounty expires before doing anything here.)

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    $\begingroup$ Generally speaking I think this type of question would be great as a CW question, and could garner some very fine answers if allowed to survive. My own preference would be to keep the question pretty soft and not too tied down to the specific set-theoretic context that first gave rise to it in your own case (although of course you can and should mention that), because it really is of interest in mathematics much more generally. I like your short version of the question. I'll step back and let others respond, but I hope it flies (and would be slightly disappointed if it doesn't). $\endgroup$
    – Todd Trimble Mod
    Jan 11, 2015 at 6:38
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    $\begingroup$ I concur. Meanwhile, you might find some of Colin McLarty's recent paper helpful. Even though these are concerned with the algebraic geometry story, the presentation pays close attention to set-theoretic issues. Further to this, topos theory - which has both geometrical and logical aspects - provides a general setting for cohomology $\endgroup$ Jan 11, 2015 at 17:01
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    $\begingroup$ I agree with Todd. I think it would be fine to migrate the question to MO. Making it CW would probably help, as there's an ocean of near-isomorphic answers that would appeal to people with different sensitivities. $\endgroup$ Jan 11, 2015 at 19:47
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    $\begingroup$ Are you aware that your bounty expires in less than two hours? You have two answers on MSE waiting for you. $\endgroup$
    – Asaf Karagila Mod
    Jan 15, 2015 at 18:03


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