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    instead of referring certain OPs to math.stackexchange we would suggest that they drop their math courses for PE courses.


    The ones I would suggest that are those that I doubt take any math courses to begin with...

    How do you drop an empty set?

    • CommentAuthorWill Jagy
    • CommentTimeApr 21st 2012
    Bill, you should see some of the astonishing crap that does make it onto MSE.

    Found it, Gerry Myerson did make one request along your lines,

    Thanks, Will. Gerry's request is very reasonable and well worth repeating.

    • CommentAuthormarkvs
    • CommentTimeApr 21st 2012
    @Bill: What if a person who asks or answers the question clearly does not know some basic math (like what the polygamma function is)? Where should he/she be referred to? About MSE - I have never visited the site, but judging by comments on MO, it is a giant landfill of MO waste populated by undergraduate students asking homework questions (in fact that is why I never visited it).
    • CommentAuthorAngelo
    • CommentTimeApr 21st 2012
    To markvs: I have no idea what the polygamma function is. Does this make me incompetent to ask or answer questions on MO?
    • CommentAuthorWill Jagy
    • CommentTimeApr 21st 2012
    Angelo, see which seemed pretty hairy for a while. After the fact, I think we could call this an insider joke.
    • CommentAuthormarkvs
    • CommentTimeApr 21st 2012
    @Angelo: I was addressing Bill. The answer to your question is "Of course not". My point is that nobody can know all math and even all basic math. Hence we should not judge harshly those who, in our opinion, do not know some basic math.

    @markvs: I can assure you that there is a lot of junk on MSE. I sometimes feel a bit bad that the dominating tag is [homework], alas it is not all bad. There are many interesting questions and many wonderful answers as well.

    • CommentAuthormarkvs
    • CommentTimeApr 22nd 2012
    @Asaf: The fact that "homework" tag even exists makes MSE completely unsuitable for me. It is cheating to ask for help with homework on the Internet. Answering such questions should end the carrier of any mathematician. At least I would not want to work with such a person in the same department.
    @markvs: Would you be willing to work with someone who wrote a textbook that answers questions that have appeared somewhere else as homework in the same department?
    • CommentAuthormarkvs
    • CommentTimeApr 22nd 2012
    @Michael: I am not sure you understood what I wrote or that I understand what you wrote.
    • CommentAuthorAngelo
    • CommentTimeApr 22nd 2012
    I guess this will be another overheated discussion. Have fun.
    Helping with homework is relative.There's a lot between writing down a complete solution and saying "It might be helpful to look up what the polygamma function does.".

    @markvs: When I have office hours and students come and ask for my help solving homework questions, I show them how to solve one of the questions and we review the solution. Do you object to open hours? Do you object to answering questions in class or exercise lessons?

    Writing a complete and detailed solution to one problem with explanation on how the method works can have much better results. I agree that students need to learn how to tackle problems on their own, however you must have some basic tools in order to tackle problems. Sadly, not all teachers are that great and some students really fail to learn from their teachers. In that aspect I find that helping other students - even in their homework - can be very useful for their development.

    • CommentAuthormarkvs
    • CommentTimeApr 22nd 2012
    @Asaf: If you teach the class, then you have to help your students. If students of other professors come to you for help - it is illegal (cheating) unless their professor explicity allowed that, which happens, but rarely. The students in the US have to sign an "honors code" document, in particular, to prevent cheating.

    So asking my friends for help is illegal? Interesting life you have there in the USA.

    • CommentAuthormarkvs
    • CommentTimeApr 22nd 2012
    If the professor does not allow outside help, yes, it is illegal (if I find out, it means an automatic "F"). I usually allow students in my class to work together. Most of the time they are allowed to use any books (and that involves documents found by Google). But they have to find and understand all that by themselves without outside help. Some professors do not allow use of the Internet at all (and then most students don't use it, which - I understand - is hard to imagine from outside the US, but most students respect the honors code). If students have any questions including questions about homework, they need to contact their professor.

    If I were told that as a mathematician I will not be allowed to ask other mathematicians, consult the internet, books, or other people in general I would probably quit now and find something else to do.

    I understand that this is how the system in the USA works, but you have to remember that a lot of the users on the internet are not from the USA, and are not signed on this strange "honors code" which disallow discussions like that. If people respect the honors code, then surely most of the student asking homework questions are not those signed on this paper to begin with.

    Lastly, I should point out, people that cheat and fail tackling problems are not likely to become competent mathematicians, and will likely fail or retire from mathematics eventually. People that enjoy mathematics, even if they do get the solutions given to them, will sit to understand them on their own. How different is that from finding the solution in a book or a journal?

    (Yes, I am well aware - from my own experience as well - to the vast difference between reading through an endless pile of books and asking someone, even your professor, for help. However if you wish to learn you will learn. The powers of curiosity are amazing.)

    I am not sure that this rule about getting help or not getting help from other professors is completely universal. I work at a small department where it is understood that help may be asked of others. Furthermore, it seems a little ridiculous to have a tutoring center and at the same time not being allowed to ask other proffessors for help. About signing honor codes, that is also not completely universal.
    I think that every professor should make clear to his or her students what kinds of collaboration is allowed, though I can't imagine not allowing them to eg talk to each other or scour the library for other sources. I do agree with Mark that asking for homework help on the internet is, at the very least, ethically dubious. I'd be pretty angry if I caught my own students doing it, though I don't think it would merit an instant F.

    Honor codes are also not universal. My own institution (Rice University) has an honor system that works pretty well; however, I remember when I was a grad student at the University of Chicago someone asked Paul Sally at a teaching meeting whether Chicago had an honor system. His response was "An `honor system' usually means that the faculty have the honor and the students have a system'".
    It is a bit strange to discuss M.SE policy with respect to homework on MO meta. Unless of course the argument is that one mustn't refer anyone to the cesspool of immorality that is M.SE, to prevent the corruption of innocent souls. The discussion is very informative though, I wasn't aware of this strict honor code system adopted in some US universities.
    • CommentAuthorWill Jagy
    • CommentTimeApr 22nd 2012
    I do not have permission to do this, but what the hell. Our own Yemon Choi, with an unfortunate sense of propriety, posts questions he feels are sub-MO in the cesspool of homework, and nobody can do this one:

    @Will: Maybe no one can do it because his question does not violate any homework related rules? :-)

    • CommentAuthorWill Jagy
    • CommentTimeApr 22nd 2012
    Asaf, that would explain it. Most fear the dark, but there are those who come to desire it, and fear the light.

    For those who fear contagion, it is the proof of Lemma 5.1 in that lacks detail. Yemon took a special case and made that an MSE question. Daniel Rider died in 2008. I have written to one student (Ng) and one occasional co-author (J. Marshall Ash), maybe something will come of that. My computer experiments say the damned thing is true, and I finally found out why the exponent 1/2 is (probably) correct and in any case optimal... See also
    • CommentAuthorgrp
    • CommentTimeApr 23rd 2012
    I think it is appropriate to ask for a proof or a reference request on MathOverflow, especially if it is made clear what legwork has been done. If you are worried about offending Yemon's sense of propriety, you might formulate a more general version, and ask if that or anything very close is true and proved in the literature. For example, for n=2 and unit and 1 replaced by alpha times unit and alpha, it is not clear to me whether an alphha version of the inequality should hold for any real number alpha other than 0 or 1. I think such a question is worthy of MathOverflow.

    Gerhard "Ask Me About Questionable Propriety" Paseman, 2012.04.23

    Yemon's question looks to me a good one for MO.

    If one carries the implicit argument of the original post further, then 1/2 to 2/3rds of US institutions of higher education should not bother having mathematics departments. (Honestly, less renowed colleges working with less prepared and less capable students graduate less than one student capable of writing any reasonable proof per year.)

    Then again, by that argument, it's not clear what departments these places should bother having at all.

    I just heard from someone affected that it is now the second year in a row that an idiot in the honors intro sequence (295-296 + 395-396) at Michigan posted take-home exam questions on math.SE, thereby invalidating the results of the exam and forcing all of the other students to take a quickly-thrown-together in-class exam. It is a very serious problem, but since math.SE is not run by people in the mathematical community (and is also home to many people who are willing to do other people's homework problems in order to get points), it doesn't seem like there's any sort of obvious answer. We could try to petition stackexchange and ask them to crack down on cheating, but I can't imagine we'll have too much success.

    • CommentAuthorsimoncfr
    • CommentTimeApr 23rd 2012
    Doesn't it seem more reasonable to warn the students in that sequence that sites such as math.SE will be watched, and what the consequences of posting the questions will be? I'm sort of surprised that the onus should be on math.SE to keep an eye out for the honour codes of differing universities out there...

    Harry, I saw on the deleted list several closed and deleted questions which someone pointed out were from the said exam.

    I can assure you that as soon as the moderators see these things they get deleted, and if they don't see them fast enough the 20k users (which are capable deleting closed posts immediately without a day+ waiting period) usually do that.

    You are wrong to say, by the way, that math.SE is not "run by people in the mathematical community". It is true that the software and the servers are maintained by the SE guys, but the moderators of the site are two "fully licensed" mathematicians and two mathematics students (there should be another moderators election soon). All of which are also MO users by the way. No one supports cheating on math.SE, the fact that people are willing to help with a homework problem is a whole other thing. When a user is found to be using math.SE for cheating in take-home exams (which is a whole other thing compared to asking a homework question) they are almost always banned (I cannot recall a time when they weren't).

    Dishonest people existed long before the internet and math.SE (or MO for that matter), and they will continue to exist long long after the internet will collapse and we will resort to carrier pigeons sending binary strings across vast distances again. Had the said student used a different forum? IRC chats? Usenet? went to a different university and asked a professor there? How would that be any different?

    If anything the fact that the student used math.SE made it visible and easier to know that someone has been cheating.

    • CommentAuthorgrp
    • CommentTimeApr 23rd 2012
    Interesting response by the department to the take home exam posting. Do you know if the department has a policy or in-house guidelines to deal with such a situation (Internet aided cheating)? I can imagine a well-prepared course having a set of fallback exams to handle such situations.

    (I liked the approach taken by the organizers of a recent US Sudoku competition, when they challenged the validity of the initial 3rd place winner: they gave him the same tests to take over again under supervised conditions, and the second time he was unable to complete them, much less post qualifying times. It may still be possible to deal with such things on a per-student basis.)

    Gerhard "Ask Me About Supplemental Education" Paseman, 2012.04.23
    • CommentAuthorWill Jagy
    • CommentTimeApr 23rd 2012

    @Will: I was lurking here on meta, which is how I saw that question.

    • CommentAuthorWill Jagy
    • CommentTimeApr 23rd 2012
    George, good, that's why I posted it. The first time Yemon did this it seemed to make more sense, it was an exercise from a specific and well-known book, MO has mostly been against exercises. I posted something here, Noah Snyder saw it, and finished an answer. However, it was for Yemon's research, for whatever reason it was something he could not quite get himself. This time, Yemon did translate his result into something sort of appropriate for MSE, but I really do not see the need. Well, whatever I do not know about Yemon, he is very polite and painstaking, if he wants to put some questions on MSE and does not slap me around for advertising them here, I guess we have a working system.
    • CommentAuthorYemon Choi
    • CommentTimeApr 23rd 2012

    My thanks to Will for bringing up the question (I think this is the second time he has done this, and the second time that someone reading on meta has provided a solution) and for promoting it. Thanks also to George for the solution, which I will try to read later once my sleep-deprived brain has rebooted. Several other inequalities in Rider's paper also have a probabilistic feel, so I think George's argument is very likely to be more or less what the author had in mind.

    I can't claim any "unfortunate sense of propriety" as I was really following the example set by Matt Daws, cf. this question. To be fair, I had intended to move the question over here in the next few days if no solution turned up on MSE. But thanks for the moral flattery :)

    • CommentAuthorWill Jagy
    • CommentTimeApr 23rd 2012
    Cool, I've been looking for an example of strikethrough, Dawes has some,
    <strike>I _think_ I can prove......... need.</strike>

    Nice argument, George.

    • CommentAuthorMariano
    • CommentTimeApr 23rd 2012 edited

    @Harry, someone does some stupid in Michigan and it magically becomes the responsability of people who did not even know about the existence of the exam?

    If someone asks me a question, I will do my best to answer. And this on MO, math.SE, the bar at my university, #math, &c. If they should not have been asking it, it is their problem.


    Back to my original post. Someone asked recently

    If $A$ and $B$ are bounded non empty subsets of the reals, is glb$(A)\le$ glb(B)$? Upon prompting, the OP agreed that the question should have also said that $A$ is a subset of $B$.

    A MO member (OK, a student) suggested posting in on SE.

    • CommentAuthorYemon Choi
    • CommentTimeApr 23rd 2012

    If they should not have been asking it, it is their problem.

    Actually, no. It seems like it would be the problem of the poor sod who went to the trouble of writing an exam.


    @Mariano: Come back to irc, we miss you dearly.

    Well, for whatever it's worth, I won't automatically attempt to answer every question asked of me, especially if something about it doesn't smell right.
    Alexander Woo wrote, "(Honestly, less renowed colleges working with less prepared and less capable students graduate less than one student capable of writing any reasonable proof per year.)"

    I know this is not exactly on topic, but... this phenomenon (that a ridiculous number of students at many schools manage to graduate without any competence in their disciplines or, on a smaller level, that students in a given course don't really learn much of the material covered) is something I am very interested in discussing or reading about. It seems to go completely unacknowledged among the professors I know, but seems very plainly true. Is this something people know but pretend not to for various reasons? Or is this an unpopular opinion, and most people don't really believe this happens? I don't suppose there is some forum where it would be appropriate to discuss this issue, or someone here who would like to exchange a few thoughts about it via email? I am a little reluctant to bring it up with the professors I know in person. ("Don't you think a significant portion of your professional life is a waste of time?")
    • CommentAuthordeane.yang
    • CommentTimeApr 28th 2012
    Mike, you're touching on a sore point that deserves a lot more discussion but not here.

    @Mike, I agree with deane.yang on this. Perhaps the new academia.SE site will be a good place to discuss that (although SE sites are never a good place to discuss something...)

    Okay, thanks. I was certainly aware that this was not really a good place for this topic; as I said, "I don't suppose there is some forum where it would be appropriate to discuss this issue, or someone here who would like to exchange a few thoughts about it via email?"

    I'll take a look at the academia.SE site and see if it's possible to turn this into an appropriate question there.
    @Mike, You can also try the Chronicle of Higher Education forums. Be aware though that this issue has in various ways been discussed to death there (several times prompted by me), and you might want to wade through a bunch of old threads before posting if you actually want serious replies.
    • CommentAuthormike3
    • CommentTimeMay 4th 2012 edited
    I'm curious about this: if it is true "that a ridiculous number of students at many schools manage to graduate without any competence in their disciplines or, on a smaller level, that students in a given course don't really learn much of the material covered", then what does one need to do if one wants to get competence? What kind of schools should be gone to, etc.?

    @Mike3: At all of those schools (or at least the vast majority of them) a student CAN get competence by doing the work assigned, and asking the professor for help if needed. Let us imagine a history course. One student gets his term paper from the internet, and passes the course, but gets no competence. A second student writes his own term paper (asking the professor for help in finding references to use) and DOES get competence. But of course all the work on the term paper cuts down on his PARTY TIME, which is more important!!! On the other side, investigating term papers for plagiarism would cut down on the professor's RESEARCH TIME, which is more important!!!

    But, as noted, this type of discussion probably belongs elsewhere...