It seems from the comment discussion at this question that perhaps we need to revisit the issue of questions from graduate-level texts. I must confess to finding Sam Nead's position overly doctrinaire, but perhaps I am out of step with the community consensus.

Thoughts?

There is no deterministic way of knowing a priori to asking that the answer is "a straightforward argument".

Sam,

Your first comment on the thread linked by Yemon begins "I think this question is better suited for stackexchange." Why is it that you prefer lists of solutions to the problems in Thurston's book to appear on mathSE?

My own opinion is that discouraging this type of question is bad for MO. It needs a certain number of questions at this level to continue being entertaining for people who like answering grad level questions in their own area---everybody likes a little diversion now and then. And on the other hand, it's good if it continues being a place where mathematicians can come for help outside their own area. It would be a shame if MathSE took over that role.

@Sam: It seems to me that your objection to the question is that it tells you where it is coming from. If Lucy had asked the same question, leaving out the bit about where the question came from, would you still object? Both answers seem difficult to defend. Either way, I guess the argument would have to boil down to, "people (either including or excluding Lucy) should work some things out for themselves."

First of all, there is nothing you can do to keep people from cheating. Answers to answered questions are increasingly more available. Secondly, this is a good thing. Sure, it builds your character to work out many things in mathematics, but you don't refrain from reading books and papers which just give you the answers. Moreover, there is no amount of hand-holding which will make mathematics easy. Understanding the answers is more often than not enough of an exercise in itself. And even if it weren't, it's not like we're in danger of running out of new mathematics.

The "people should work things out for themselves" objection to MO (or to certain questions) simply doesn't withstand scrutiny.

My own opinion is that discouraging this type of question is bad for MO. It needs a certain number of questions at this level to continue being entertaining for people who like answering grad level questions in their own area---everybody likes a little diversion now and then. And on the other hand, it's good if it continues being a place where mathematicians can come for help outside their own area.

Yes! Aside from making it easier to get your little lemmas outside of your area out of the way, wonderful mathematics gets done when the asker and answerer discover they have complementary skill sets which together can tackle some new problem.

I'll backtrack slightly: some questions from textbooks do make good MO questions; such as this one

But IMO MO should not include a repository of answers to questions from textbooks.

Sam,

I haven't the slightest idea who you are, and I assume that you are much less grating in person than online. Pseudonymity has its advantages! An informal poll of colleagues suggests that a large plurality of mathematicians believe that online discussion of textbook problems, especially outside one's area, can be a fun&rewarding way to spend an afternoon; your eagerness to impose a gag order on MO to avoid spoiling a few exercises seems pretty selfish to us. The OP was direct and honest: she had tried hard to solve the problem and came to MO asking for help after that failed. You're interfering with the proper functioning of the site.

Preserving comment threads on meta is standard practice for long comment threads that get off the topic of mathematics. We want to be able to refer to the record of what was said without leaving it up on the main site.

Dear bsteinberg,

Since I upvoted Lucy's comment, perhaps I owe you an explanation.

My perception is that Mathoverflow has lately become much less friendly to newcomers, including professional mathematicians and advanced graduate students. There have been several recent instances of questions that were clearly not undergraduate-level from new users who were advised to post on math.SE instead (sometimes with the incorrect suspicion that their questions were homework). Especially in this particular case, I am doubtful whether math.SE would have been a good fit, simply because of the current (small) group of expert mathematicians on the website (who lean mostly towards algebra and number theory), although Ryan Budney might have answered it; my impression of math.SE is that, unlike MO, it is not primarily academic mathematicians who answer most of the questions there (even the more advanced ones).

I am somewhat uncomfortable with this trend, and I know I would probably have left the community if my first post had occasioned such a controversy. Similarly, if I asked a senior mathematician that I did not know previously a question that came up in my reading, and was told the question was too elementary for them, I would probably be reluctant to contact them again. The effect would probably be heightened on a widely read professional board. As far as I understand, MO was (at least initially) supposed to cater to mathematicians in the way a large seminar might: that is, questions asked by an outsider that a specialist might find elementary were to be welcome. If this has changed, perhaps the FAQ should be updated to reflect this. However, I suspect such a change would make MO much less useful for many of its users: I know I at least have learned a lot from non-specialist questions, and the votes that some of them have gotten suggests others have as well.

Moreover, I think the trend tends to affect new users more; for instance, when I asked an elementary algebraic geometry question a year back, I received several helpful answers and comments. Had I been a new user then, I suspect the outcome would have been different. It seems a bit unfortunate to me that new users do not receive the same generosity or at least benefit of the doubt.

Finally, it was not my belief that you or your particular comments were sexist that prompted me to upvote Lucy's remark; rather, it was the (possibly incorrect) suspicion that users with female usernames may be, in general, more likely to attract such comments (in general).

Regards,

Akhil

N.B. As I am a student with fairly little experience in the mathematical community, who uses MO almost exclusively to ask rather than answer questions, my post should probably be assigned correspondingly little weight.

Thank you, Anton, for injecting some level-headedness into this discussion. I particularly liked your "How would you respond if a colleague knocked on you door with such a question?" standard.

Like many of the other commenters in this thread, I am unhappy with the level of nit-picking and fussiness with which first time questioners are often confronted. I wish that those of you who frequently write such critiques would back off a notch or two. Even if you don't mean to be unfriendly or unhelpful, it often comes across that way. (Just to clarify, I'm not talking about 90-95% of the questions which get closed or criticized. I'm talking about the remaining 5-10% which are asked in good faith by research mathematicians or grad students.)

@bsteinberg: I can understand why you are upset, but I think Lucy's comment fell slightly short of accusing you of sexism. I upvoted Lucy's comment [at least I think I did; it's now been deleted so I can't confirm], but it was because I thought there had been too much nitpicking of her question, not because I supported her suggestion that sexism might be playing a role. I don't think you were being sexist.

@markvs: Perhaps your remark about "psychological problems" was some sort of well-intentioned joke, but I kind of doubt it. If, as I suspect, it was intended as a criticism of the OP, then I think it is a pretty obnoxious thing to write here, and also completely unsupported by anything written in the comment thread. You might want to consider retracting it. If I've misunderstood your intensions I apologize.

Before the thread gets closed, can I thank everyone for their responses and clarifications - I was otherwise occupied yesterday so could not contribute. I had intended the question to be more about the practice of asking questions from said books, especially since I originally opened a MSE account solely for the purpose of asking how one solves one of the exercises in Isaacs's book on character theory, and since got the impression that the question could have been acceptable for MO.

Regarding the other discussions: I will also own up to being one of those 13 upvotes on the comment left by Lucy, and I am very sorry for any insult it has caused Ben. My hasty reading of the comment caused me to upvote, based on the 1st part ("other people have not been treated this way") for reasons similar to those mentioned by Akhil Matthew. Since I had no supposition that Ben was being sexist, as I recall full well the example he gives above where a male student was given the same advice, I did not really register that the second part of Lucy's comment could be interpreted as an accusation against him in particular. (It's unfortunate that one cannot rescind votes on comments.)

I also agree wholeheartedly with what Ben has said in his last comment, and hope that he will in time return to MO in some capacity.

Back to the original subject: here is another... http://mathoverflow.net/questions/87085/maximal-cohen-macaulay-module

@markvs; remember that email addresses are not verified by the software. I have been unable to contact 'Lucy', and personally have no idea who she is.