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    • CommentAuthorWill Jagy
    • CommentTimeDec 2nd 2011

    Apparently SVMs are ubiquitous and don't need explaining. I guess that's us told, then.


    From a later comment by the OP (written rather politely), it has to be said:

    In the department where I work, everyone from number theorists to harmonic analysts knows what an SVM is. It's as basic as knowing what an integrating factor is for ODEs. If this is true across an entire math department, it should surely be true of a sizable number of specifically functional analysis experts of a math website. If others don't know it, that's fine. But again, they should just ignore the question rather than calling for it to be closed.


    I don't know what an SVM is, but we also don't ask questioners to define 'adele' (and I don't know what that is either). I have heard the term enough that I can accept that it is a common concept in some area I don't understand much about.

    As a general question which I have raised before, are mathematical modelling questions within the scope of MO?

    Let me rehash from earlier debates which never reached any conclusion. There is a large continuum in applied mathematics, ranging from people whose goal is to prove theorems that happen to be on questions close to applications to people who have no interest in proving theorems but rather are interested in combining known theorems and algorithms to model systems coming from other disciplines and calculate features of these systems. The issue is whether questions about applied mathematics far away from the theorem proving end are within scope.

    Frequently mathematical modellers are considered mathematicians, either because the disciplines to which they apply their work has only experimentalists and no significant tradition of theoretical modellers, or because they are interested in models from many different disciplines, or both.

    For an example of the latter, if you have a large integer programming problem you want to solve, there are experts in integer programming who may have never proven a new theorem in their life but who are very familiar with existing techniques and are capable of combining them in creative ways in order to find a solution (or sufficiently good approximate solution) to your problem with a feasible amount of computational resources (i.e. decades rather than millenia of processor time).

    • CommentAuthorWill Jagy
    • CommentTimeDec 2nd 2011
    I just looked at

    which, perhaps because I'm not registered, has a banner across the top,

    "Welcome to Q&A for statisticians, data analysts, data miners and data visualization experts — check out the FAQ!"

    Meanwhile, R. Hahn said "Support vector machines and radial basis functions are common enough in machine learning and data mining"

    and Yemon said "Reproducing kernel Hilbert spaces are of course well studied and much beloved; but not everyone grows up with the same acronyms as you do."

    In fairness, I seem to remember defending someone's unexplained use, in a question about Banach spaces, of MAP and some other standard acronyms in that area. (The question itself was unsuitable because it was asking if anyone had solved a notorious open problem in the field, but I thought the use of the acronym in that case was not the problem.)

    • CommentAuthorquid
    • CommentTimeDec 2nd 2011 edited

    I agree with Yemon that over-usage of acronyms (originally I typed pseudonyms :D) is a problem. Also, the question could be better written in general.

    That being said, for me typing svm into Google the third item after two obvioulsy unrelated things is the wikipedia page of 'support vector machines' and there are a couple of other relevant hits. So, at least with some moderate effort one could find this out.

    IMO the first comment is the most 'toally inappropriate' thing in this entire exchange. [ADDED: the comment in question was delted by a moderator; so the curretnly first is not meant.]

    For the question itself I have no real opinion; but apparently at least Suvrit (not to say others don't but he documented it somehow) has an informed critical opinion on it.

    SVM is indeed a very common acronym among those who care about such things, and a lot of applied mathematicians do, so I don't think there's anything wrong with using it without explanation; I like Alexander Woo's analogy with adeles. However, it's not so common that every mathematician should know it, so of course the polite thing to do if asked is to explain it, rather than insisting vociferously that it requires no explanation (although Igor's initial comment could have been phrased more politely). Furthermore, the sentence "In the department where I work, everyone from number theorists to harmonic analysts knows what an SVM is" seems highly misleading, considering that this department is apparently the School of Engineering and Applied Sciences at Harvard, which as far as I know has no number theorists and only very applied harmonic analysts. (Maybe I'm wrong about this, in which case I'll have learned something new and interesting about SEAS.)

    In any case, it's not clear to me whether there's a reasonable MO question here, since it's posed rather vaguely. I agree with Suvrit that it comes across as a textbook question; it reads like a slightly more detailed version of "please explain how to use a nonlinear SVM," which would not in itself be a research-level question, even though SVMs are certainly a graduate-level topic used in research. If there are deeper issues being raised, then they need to be formulated more clearly. I'd be happy to vote to re-open if that is done, but I don't see a good reason to re-open it as currently written.
    • CommentAuthorAbe
    • CommentTimeDec 2nd 2011
    This debacle has left me feeling less than inspired by mathoverflow. I think there are faults all round. First of all, the poster should have taken into consideration the current balance of mathoverflow, in which his area seems quite underrated, and written a question that was more easy to understand for a general audience. That's a necessary evil unfortunately of the fact that mathoverflow is well developed in some areas of math and not so in others. His responses are also belligerent, and against the spirit of mathematical debate.

    However, some of the responses by mathoverflow members certainly do leave a lot to be desired, and, I think, really go against the spirit of this endeavour. I think it's important for mathoverflow to encourage all areas of math research to be represented, even those that overlap with physics and computer science. Hence members do have to be more willing to partake in discourse with posters of such questions. There's a polite way of telling a poster to revise and restate his question without resorting to mocking/provocation.

    On a slightly related note, it has become clear that certain MathOverflow members, despite being fully grown adults and professional mathematicians, are incapable of commenting constructively. If you see inappropriate behavior, please don't hesitate to flag the question or answer for moderator attention with a brief explanation, and I will find a way to deal with the problem.

    • CommentAuthorgrp
    • CommentTimeDec 2nd 2011
    I apologize for my part in the endeavour. What I thought might be a good way to get the point across that the question was illsuited for MathOverflow developed into an opportunity for me and the poster to exhibit more bad behaviour. I would not like to reward the initial behaviour of the original post however. Perhaps a compromise can be reached; a moderator can delete my nonanswer or the entire question and a rephrased, more respectful version of the question can appear? If sufficient explanation and motivation appear I would be willing to delete my own non-answer.

    Gerhard "Mea Culpa, Mea Minima Culpa" Paseman, 2011.12.02

    Gerhard, I'm afraid I deleted your answer shortly after writing my previous comment. I agree that the questioner's behavior was far from ideal.

    • CommentAuthorWill Jagy
    • CommentTimeDec 2nd 2011

    I forwarded an email to several of you. Now the writer says he is not the one who posted the question. He really wants everything computerish to be accepted as mathematics.

    Dear Will,

    That was a rather strange and incoherent email you forwarded to me. The writer does not seem to be connected to the discussion in a substantial way, and I am reasonably certain it is not the person asking the question. If this progresses to harassment, you should probably contact authorities with legal power instead of MathOverflow moderators.

    • CommentAuthorWill Jagy
    • CommentTimeDec 2nd 2011
    Scott, thanks. It may come to that.

    I forwarded that email because I assumed EMS and James were the same person, but that is not the case.

    Nilima has not been involved, but thought the question not that bad. I asked whether she wanted to supply an improved question. It's late, so I don't expect a reply on that for several hours...
    • CommentAuthorNilima
    • CommentTimeDec 3rd 2011 edited
    Dear Will, I am by no means an expert in the (vast) area of machine learning. As a consequence, I see an interesting question in the OP's posting. But I am uncertain about the level of the question. The whole comment flare-up is another aspect entirely, on which there is nothing new to say.

    Here is the difficulty: *what is rudimentary for one mathematician may not be for another*. Our discipline is large enough that there are vast areas which appear to evolve with very little contact. This sorry episode has very little to do with 'pure' v/s 'applied', and more to do with the lack of a shared jargon.

    Reformulated to include motivation and background, this is a question which is interesting to me. The OP points out he is interested in poselets and nonlinear kernels, and in that setting, I didn't know how to answer his question. If he'd included some of this background in the question rather than in the comments, I think it may have been a better question. It may have lived on in some small corner of the site, viewed by 5 or 6 people, and hopefully answered quickly by one.

    Quite possibly, this is a question readily answered by a machine-learning expert (someone like Suvrit). Indeed, it may be elementary in the area of machine learning. I don't know the area well enough. I was intrigued by the question, and learned from Suvrit's comments.
    • CommentAuthorWill Jagy
    • CommentTimeDec 3rd 2011
    I heard back from Suvrit, and he left a final comment at the question at about the same time. I had not noticed that he had actually left two comments with some mathematical content, the second essentially an answer to the question.
    One reason I like MO is that I can often learn something about areas distant from my own interests by reading questions (even ones that are too elementary for the specialists and therefore get closed), answers, and comments. So obviously for my purposes, a post about SVMs (which I had heard of but didn't remember much about) and RBFs (which I hadn't heard of) is useless and I'd just ignore it. I'd be much happier with a well-written question from which I can learn something. But the person asking a question isn't necessarily interested in my learning something; he or she just wants an answer and therefore can formulate the question in a way that would be understood only by those experts who might provide an answer. That leaves me somewhat unhappy, but with no real ground for complaint.

    I am inclined to agree with Andreas.

    There are currently two votes to reopen. While I have my misgivings about the question, and am not entirely happy with the attitude/assumptions of the OP as shown in comments, I am casting a third vote to reopen so that (a) the question might be improved (b) an answer that Suvrit appears to have sketched in the comments can be added as an actual answer, CW if necessary.

    • CommentAuthorMariano
    • CommentTimeDec 3rd 2011


    If we were to tend to a place where questions are written so that non-experts can't even tell what the subject is, I would get bored rather fast!

    • CommentAuthorquid
    • CommentTimeDec 3rd 2011 edited

    I also just voted to reopen.

    Added: Shortly thereafter final vote occured. Question open.

    This brings up the whole issue of whether "please explain concept X from standard graduate texts" is the right sort of question for MO, since it's now clear from EMS's comment exchange with Suvrit that this is exactly what the question was. (I had previously wavered on whether I thought so, since I wondered whether EMS was trying to get at something deeper and just not formulating it clearly.) My feeling is that it's appropriate if there's something interesting or nonstandard about the question, or if it deals with real subtleties or common misconceptions. However, I would vote to close if someone asked "please explain step-by-step how schemes are formed by gluing together affine schemes", and this question is the machine learning analogue of that.

    In the comments, EMS seems to be asserting that according to the FAQ, every question that arises while reading a graduate-level book is appropriate for MO. That's not how I interpret the FAQ, and I'd argue for changing the FAQ if other people (besides EMS) are interpreting it that way.

    I'm a little confused. I'm not even acquainted with the subject of the thread we're talking about, but from reading this thread it seems like the original question is off-topic for MO. So why did people vote to re-open? For example, quid voted to re-open but from his comments here I would have thought he should not. What's going on?

    I wouldn't say it is off-topic subjectwise (questions about support vector machines should be welcome on MO), but rather not research level.
    • CommentAuthorquid
    • CommentTimeDec 3rd 2011

    @Ryan: Yemon gave a quite detailed explanation why he voted to reopened. And I said that I also vote to reopen, in the sense of for basically for the same reason.

    I am not quite sure what you mean with I 'should not' vote to reopen?

    24h ago I said I have no real opinion; quite a bit of things happened in between, now I have one, what's wrong with that?

    • CommentAuthorWill Jagy
    • CommentTimeDec 3rd 2011 edited
    Well, never mind.
    • CommentAuthorquid
    • CommentTimeDec 4th 2011 edited

    @Will: Thank you.

    • CommentAuthorWill Jagy
    • CommentTimeDec 4th 2011
    Alright, quid.
    • CommentAuthorWill Jagy
    • CommentTimeDec 4th 2011 edited
    At the recent question I put roughly this message:

    I know nothing about this, but I can tell you that few on MO know more than that. I am confident that you will have a much better time at $$ $$ $$ $$ where the search feature lists 314 questions tagged machine-learning, 96 questions tagged data-mining, 74 questions tagged algorithms, 45 tagged svm, 41 tagged neural-networks, 18 tagged boosting. From it is clear your question will do well there. Also check and

    and the OP indeed posted the question as

    Edit, 12:26 AM Pacific time, a high-rep user edited the title and then tweeted something, that seems promising. Or maybe SE tweeted something.
    • CommentAuthorWill Jagy
    • CommentTimeDec 5th 2011
    • CommentAuthorYemon Choi
    • CommentTimeDec 5th 2011 edited

    This new question seems relevant to the points raised by Alexander Woo. We clearly have an FAQ that means one thing to many of us and another to a small but discernible potential audience, who consequently take umbrage at being told "read the FAQ to understand why we will probably close this question".

    • CommentAuthorquid
    • CommentTimeDec 5th 2011

    @Yemon: Could you please spell out what this thing the FAQs mean to many of us is in your opinion (just for math, let us ignore all soft things). Perhaps in an another thread or also here. This particular question is perhaps not an optimal instance to illustrate this (in some sense both). But the average standard applied over different subfield of math on MO in my opinion so different, even for the highly represented ones, that things are confusing. In general I think I meanwhile have a quite good intuition which questions will and will not 'cause problems.' But if I should explain why this is so I could not give a coherent explanation. Or if I tried this would rather involve explantions of the form: Active User A is rather strict and in field F therefore standards in field F are higher than in field E where Active User B is a main MO authority and is less strict. Questions in applied field AF have in general a hard time because Active Users C1 to C5 already don't like the style in which things are expressed and thus when in doubt likely close. And so on.


    @quid: thanks for calling my bluff ;) I guess I meant this bit

    Though there are no hard and fast rules about who may post here, the intended audience is professional mathematicians, mathematics graduate students, and advanced undergraduates. If your question is closed as "off topic," it might be because it was too elementary. This doesn't mean that your question is "bad," just that MathOverflow isn't the right place for it.

    Now my understanding was this was meant to discourage questions which are in some sense "too elementary", or "in undergraduate student mode" - that's not a question of topic, but a question of substance or depth. However, I may well have misremembered; and I am in fact ambivalent about the question I linked to (note that "many of us" sometimes includes "me", but not always). My point was more that the OP's reaction in the question I linked to seemed similar to that of EMS, as in "what did I do? what is your problem, man?"

    (While I type, it seems from the comments to the new question that this may be a case of the questioner not being sufficiently diligent in reading the papers.)


    When it comes to level, I think the FAQ should have a sentence like:

    "Ideally, an appropriate question is one for which a useful answer would help with work leading to a paper suitable for publication in a mathematics research journal."

    • CommentAuthorquid
    • CommentTimeDec 5th 2011

    @Yemon: You are welcome :) And, I like people for whom 'many of us' does not need to contain themselves; certainly better than those that take the membership of the element 'me' as the definition for being 'many of us' but I digress.

    I agree on the 'topic' and 'substance' part. But my impression is that depending on the topic the meaning of 'too elementary' changes quite a bit. Meanwhile in view of the comments, in particular BR's (and before the crosspost one) I voted to close 'your' question. Since however one interprets things I think a certain level of prior work is in order before asking a question. (In the original question of this thread my impression was eventually that this criterion was met; others had perhaps a different impression; but to decide this is always hard.)

    In general I think it is really hard to formulate the FAQs regarding this. In some sense I think it might be better to drop 'advanced undergraduate' and add the 'advanced' to 'graduate' for the description of the 'standard audience' or 'default audience'. Of course not to exclude undergraduates but perhaps more harm is done by instances were people are somehow mislead to ask too simple questions and then get 'in trouble'. Not sure though. But recently some very regular user (I believe Andy Putman but did not recheck) argued that the default assumption for users not providing background should be a PhD in maths. But this is then a quite different intended audience. And some standard argument is 'should be of interest to professional research math.', which I hardly use myself, but I would also interpret as more or less post PhD. But perhaps this is also a cultural difference, and those using professional research math actually consider graduate students as such. (Not that I would disagree that much but I would not use it like this myself.)

    I agree that "advanced undergraduate" should be dropped from the FAQ. I imagine it was intended to mean "advanced" in the sense of Qiaochu Yuan - someone who is strictly speaking an undergraduate but who might as well be a grad student. However, in everyday usage an advanced undergraduate course is one aimed at 3rd or 4th year students, and it seems reasonable to call someone taking advanced undergraduate courses an advanced undergraduate. If someone interprets these sorts of advanced undergraduates as part of the target audience for MO, then closing for being too elementary will cause offense.
    • CommentAuthorHJRW
    • CommentTimeDec 6th 2011

    I too agree that the phrase 'advanced undergraduate' should be dropped from the FAQ; my reasoning is the same as Henry Cohn's.

    +1 to Alexander Woo. That sentence would be a great addition to the FAQ (continuing under the assumption that anyone actually reads it).

    It seems to me that recently, in at least, there have been quite a lot of questions of the form 'I'm a graduate student reading book X, and I don't understand the proof of Lemma 3.14'. As far as I'm concerned, math.SE should be the first port of call for those questions. They're not my interpretation of 'research level'.

    Let me just mention that I'm aware that these proposed modifications to the FAQ run the risk of exacerbating the internet-wide perception of MO as an unfriendly place for visitors. But, for me, the value of MO lies not in the number of mathematicians who use it regularly, but in their quality. It's truly remarkable that I can ask a question in a public forum and get an answer from Ian Agol or Mark Sapir. To continue to attract world-class users, the level of questions has to be remain high. I know of at least one first-rate mathematician who I believe left MO because the level of questions wasn't high enough.

    @HJRW: the FAQ currently refers to "the sorts of questions you come across when you're writing or reading articles or graduate level books". To me that means that "I'm a graduate student reading book X, and I don't understand the proof of Lemma 3.14" is (at least potentially) an acceptable question. Moreover, I think that the FAQ is right to suggest this, because I think that such questions should be acceptable.

    I cannot speak for anyone else, but for me the occasional outbreaks of needless unfriendliness (to other people, not to me) are much more off-putting than relatively elementary questions from graduate students.
    • CommentAuthorquid
    • CommentTimeDec 6th 2011 edited

    I am strictly against that this suggested change of the FAQ would come along with raising the level in everyday practise. By contrast I am in favor for writing '(advanced) graduate student' or also without advanced or just 'not-beginning' and actually act according to this, which does not always happen in practise now.

    Afterall the site was founded by a (then) advanced graduate student (AFAIK). And, while I was not around at that time, reading older questions and what some people around since a longer while tell in the start of MO standards were lower and supposedly people were happier. No matter what is written in the FAQs 'we' will never get rid of a (in my opinion more or less constant) number of 'strange' or clearly too elementary questions. The question is what ratio of all questions this is.

    HJWR says:

    To continue to attract world-class users, the level of questions has to be remain high.

    Various people around since more or less the start say that the standards got higher. Thus, I do not think any particular action is needed so that just the standards remain high. IMO the perceived quality gets lower because some intersting content starts to be lacking. Also cf. Andreas Blass statement above (emphasize mine):

    One reason I like MO is that I can often learn something about areas distant from my own interests by reading questions (even ones that are too elementary for the specialists and therefore get closed), answers, and comments.

    So, one could also say by ever raising the standards one takes (everything) away what Andreas Blass gets in return for his 250+ answers.

    To continue on the topic of world-class users let me also quote Bill Thurston (from his profile):

    I enjoy questions that seem honest, even when they admit or reveal confusion, in preference to questions that appear designed to project sophistication.

    Judging from some of the (detailed!) answers he gave to certain questions this is not just some empty phrase. So, yes some world-class users might not get attracted to MO for one reason or another but perhaps some go more or less inactive because of a growing (pseudo-)sophistication. Could also happen. In general, from what they often answer and sometimes also ask it seems that in general various world-class users that are actually around are not that worried about enforcing most exact standards of research level. And some other world class mathematicians will never use the site whatever is done regarding standards.

    And also:

    It's truly remarkable that I can ask a question in a public forum and get an answer from Ian Agol or Mark Sapir.

    It might be remarkable, but is it really useful. Couldn't you have written an email to Mark Sapir to inquier about non-Hopfian lacunary hyperbolic groups?

    While I never asked anything so far if ever I would ask something it would be somehow graduate level, I guess, because it would be rather outside my field. I have absolutely no need for a public place to ask experts in my field. If I want to ask them something I ask them (privately). But I could find it useful to ask experts outside my field something. But then chances are this won't be really research level.

    In brief, IMO the model of MO is really useful for asking experts outside ones own field and/or for people that do not (yet) really have 'their' field (viz. graduate students). By contrast, to run some ten expert-to-expert sites on one site seems not so useful.

    ADDED: It occured to me that this could be misunderstood as me advocating that the expert-to-expert questions should not be asked at all. This was not my intention. What I mean is it would not be useful to have only those, and indeed for getting those answered the existence of the site is not so important as there would be other viable ways.


    That's eloquently put, quid. The phrase "research-level question" all by itself is ambiguous. One way it seems to be interpreted is along the lines of "question that directly arises from a cutting-edge article I'm preparing". Another interpretation might be explained by way of example: I, a trained mathematician, would like to learn more about algebraic quantum field theory, something I'm not at all expert in. In other words, I'm doing a little research in the area, not because I intend to write cutting-edge articles on it, but because I'm expanding my scope as a mathematician. Now, here's a question in AQFT, which might be easy for experts, that I'm stuck on, etc.

    One of Andrew Stacey's question might be a good example of a research-level question under interpretation number 2. My own take on MO is that largely it's for "research-level questions" under that interpretation. It can also be used for interpretation number 1, but that's not the primary mission. And I would say that graduate-student questions about lemma 3.1.1 certainly fit that bill. They could try asking on, but more and more I see people who do that and don't get an answer, and then come to MO (hat in hand, practically). I think they should feel not at all ashamed to ask on MO in the first place.

    I agree that the level of "acceptable question" has risen noticeably since the early days.

    I'd discourage most questions of the form "I can't understand the proof of Lemma 3.14 in graduate text X". If you get stuck on a lemma, I think you should try several steps before asking on MO: pausing to think and examine an example, reading on while making a note to return, and then looking for another reference if you return and still can't figure it out. There are times when this won't help; maybe you are reading a paper for which there is no other reference, and there might be something genuinely incorrect or at least cryptic about it. In those sorts of cases, asking on MO seems completely fine. However, if you are reading a graduate text in a field for which there are several such texts, then there's no reason to ask on MO every time you get stuck. In particular, I don't like questions that can be read as "Please write me an exposition of this standard fact for which lots of expositions have been written, since I got stuck on one of them and don't want to go find another."

    I agree with quid that it is important for MO to encourage questions by grad students or by experts asking about things outside their expertise. They should just be sensible and well thought out.

    I agree with Todd and others that "research level" should mean the sort of question that a research level mathematician might ask, but perhaps in a field which he or she is not an expert. In the early days of MO I remember people often saying that the ideal MO question is one which you (an expert in field X but a newcomer to field Y) would have difficulty with but could be answered quickly and easily by an expert (in field Y).

    I think that questions of the form "I'm having trouble with this detail in the proof of Lemma 3.32 in research paper P" are typically (but of course not necessarily) on topic. [EDIT: but in light of Henry Cohn's comment above I now realize that other people had in mind lemmas in standard graduate texts, which is a little different.]

    Quid's suggestion that we drop "advanced undergraduate" from the FAQ is (in my opinion) a good one. I think many, perhaps most, people would interpret this to mean "fourth year undergraduate, not first year undergraduate". The undergraduates who are advanced in the sense that we intend know who they are and can figure out that "graduate student" includes them too.


    If you get stuck on a lemma, I think you should try several steps before asking on MO

    Of course. MO is for when you're honestly stuck, after giving it the good old college try.

    However, if you are reading a graduate text in a field for which there are several such texts, then there's no reason to ask on MO every time you get stuck. In particular, I don't like questions that can be read as "Please write me an exposition of this standard fact for which lots of expositions have been written, since I got stuck on one of them and don't want to go find another."

    Agree with that too, very strongly. There is no lack of observable laziness on MO; so many cases where it almost seems asking on MO is a reflex, whereas if the OP would just think for a minute or so, the answer would be clear.

    • CommentAuthorNilima
    • CommentTimeDec 6th 2011
    I'm perhaps not the intended user on MO, and am posting here mostly because of Will's initiative.

    I work in an area which is not well-represented on the site. I recognize there are many, many sub-fields of mathematics which I know very little about, and that my ignorance is vast. I actually *like* this- it is an opportunity to learn. I'm curious about these other areas, and would like to learn more about the problems, interesting directions, and interconnections in these fields. I have a large tolerance for genuine ignorance, but little tolerance for meanness.

    What would have been a perfect variant of MO for my purposes? Say I was working on discretizing a gnarly PDE. Background reading reveals the correct setting to seek solutions are in the Nikol'skii spaces. I have no training or familiarity with these, and go look up the standard reference. The result I seek is not there, but appears true when tested on some (contrived) examples. I don't know enough to be able to prove it myself. I look on MathSciNet, but since I am not familiar with the vocabulary in the field, my search is inefficient and throws up 200 papers. At this juncture, I'd post something on MO, providing some context for my problem, and ask whether the result I seek is true. Someone like Yemon sees it, recognizes the result as Lemma 6.4 in some favorite textbook, and points me to the textbook.

    In some sense my 'level', ie undergrad, grad, etc., has little to do with the *content* of the question. If Yemon needs more information about the background of the problem to answer the question, he just asks me. I provide this, and hopefully Yemon points me to Lemma 6.4. Perhaps I'm asking, very naively, for a pointer to an exposition everyone but me is familiar with. I think that is OK. This alternate variant of MO is more about pointing people to the right resource - whether MSE or a textbook or a paper - than it is about jumping on a questioner (no matter how poorly phrased/low level the question). I'd be more likely to help out on such a site, and much more likely to ask questions.

    By and large the people on the existing MO are friendly. However, there's a nonzero (and I perceive, increasing) probability of a questioner being at the receiving end of rude behavior. This acts as a deterrent, at least for me.
    • CommentAuthorWill Jagy
    • CommentTimeDec 6th 2011
    Hi, Nilima.

    I finally got some inconclusive comments at my STATS META post,

    Quotes about, I think, the EMS question:

    @varty and Will, it is definitely on topic, so no worries in that regard. The question is not within my ken though, so I can not say what your chances are of receiving an answer. I believe a more thorough response should address the hostility on the MO site though, and how as a site we should try to handle such situations here on Cross Validated. – Andy W 2 hours ago

    @AndyW I fail to see the relevance of how MO treated the question. All we have to decide is whether such a question is acceptable or not irrespective of where it comes from and irrespective of how it was treated at the source. Of course, just as any other question, it may be unanswered for a wide variety of reasons (e.g., lack of focus/clarity, lack of experts etc). – varty 1 hour ago

    Neil Strickland wrote:

    I cannot speak for anyone else, but for me the occasional outbreaks of needless unfriendliness (to other people, not to me) are much more off-putting than relatively elementary questions from graduate students.

    Neil, you speak for me too.

    Also, too much is made of this criterion "graduate-level". It's entirely changeable: do you really know what graduate mathematicians learn in India or Indonesia or Iceland or Ireland? One of the graduate courses I took included some highly obscure corners of universal algebra, which perhaps no one else on the whole of MO knows about. If someone did happen to ask about one of those obscure corners, and I criticized their question as being "something I learned about in a first course on universal algebra", that would be ridiculous. (Yet, I perceive that that kind of criticism is increasingly common.) Graduate education also changes over time; the age range of MO users probably covers over 50 years. The concept of a "standard" graduate education is a non-starter.

    Kevin Walker wrote:

    In the early days of MO I remember people often saying that the ideal MO question is one which you (an expert in field X but a newcomer to field Y) would have difficulty with but could be answered quickly and easily by an expert (in field Y).

    I fully support that.

    My work takes me to many foreign areas of mathematics, and I'd be really sad if it wasn't possible to use MO to enlist the help of willing experts.

    That doesn't mean I don't my homework - I do. I don't ask questions on MO lightly. But it needs to be appreciated that when you're an outsider to a field, you don't have an insider's instinct for what's routine and what's difficult. You may have no idea whether you're asking an elementary question or something unsolved. And looking stuff up can be hard when you don't have an insider's vocabulary. (Who could guess, for instance, that a particular property of rings is called "Cohen-Macaulay"?) Of course, you can acquire an insider's vocabulary by going away and reading an entire book. But isn't the purpose of MO that we help each other?


    I agree with Neil and Tom (and everyone else who agrees with them!). For me, the problem with "I'm reading X and don't understand Lemma A.B.C" is not the level but the amount of thought that's gone into the question before asking on MO. What Todd says about the "old college try" (though why putting an oval-shaped ball on the ground is relevant, I've no idea) and Tom says in his last paragraph is the key: MO is not a place of first resort, it's a place of middle resort: after all the obvious avenues have been explored and the next is to spend days in the library searching through book after book, we ask on MO just to get a little help as to which book to start with (or some other help).

    • CommentAuthorgrp
    • CommentTimeDec 6th 2011
    To Tom Leinster: I am interested in knowing some of those obscure corners of universal algebra you mentioned, especially if I encountered one of them. (Partial list: tame congruence theory, commutator theory; lattice of interpretability; structure of finitely-decidable varieties; various finite basis results. If there is no intersection between your list and this one, I would like to hear yours.)

    I have my impressions on what MathOverflow should be and how it might be possible to get it there. I think it is near hopeless to modify the FAQ and other documents and get any lasting effect out of it; people are going to post what they want and MathOverflow members are going to react as they feel best. It might be useful to compare notes on various issues and see the different perceptions; implementation however will remain the same: people will vote/comment/answer as they see fit. Perhaps it is time for a census on how the membership feels about various issues, so that the community can be more self aware.

    I am temporarily abstaining from the habit of commenting on the behaviour of a questioner; this recent incident (82499) indicates that the amount of restraint I feel is needed in responding to certain types of behaviour is not enough. I hope those with more restraint will discourage the behaviour of such posters; I still think the original poster got more consideration than was fair, and this is after cutting a lot of slack in favor of the poster. I appreciate Abe's assessment on there being faults on the poster's side and the responder's side (for some of which I accept blame), but I think there should be some consensus on how to handle a questioner resistant to (culture , seminar behaviour, desired participation on MathOverflow, whatever gestalt I am thinking of but at the moment cannot express cleanly), and that it should be possible to do so without moderator intervention in cases like this one.

    Gerhard "Questions Matter; Do Questioners Also?" Paseman, 2011.12.06
    • CommentAuthorHJRW
    • CommentTimeDec 7th 2011

    First, let me say that I've found this conversation extremely useful. I think Andrew Stacey hit the nail on the head with

    the problem with "I'm reading X and don't understand Lemma A.B.C" is not the level but the amount of thought that's gone into the question before asking on MO ... MO is not a place of first resort, it's a place of middle resort

    Too often it has seemed to me that these questions have been asked instead of trying another text, asking one's advisor or even just taking some time to think about it. I realise that this has been my main objection to these questions, more than the level at which they are asked. That said, I lean towards Todd's interpretation number 2.

    Secondly, I want to emphasise that, in my comment above, I never endorsed rudeness on MO. This is a serious problem, particularly when levelled at first-time visitors.

    Thirdly and finally, in response to quid, I feel like I need to explain further why it's useful to be able to ask questions in one's own field on MO. The example that he cites, my question Is there a non-Hopfian lacunary hyperbolic group?, is a good one. He's correct that I could have e-mailed Mark Sapir, and indeed I considered doing so. Here are three reasons why I'm glad I didn't.

    1. Mark might have felt some obligation to reply, even if he is busy. By asking on MO, I don't intrude on his time.

    2. I would only have got Mark's point of view. In the end, I received three excellent answers, all of which contributed something positive.

    3. I might have e-mailed Mark directly if I was about to write a paper on the subject. But this question occurred to me at an earlier stage in my thought process, when I'm trying to get a feel for a problem and work out what might reasonably be true. As such, my question, though important to me, didn't feel urgent enough to warrant an e-mail.

    In fact, the ideal setting to ask the question would have been in person at a seminar or conference. But sometimes logistics make that impossible, and in this instance MO made a great alternative.

    • CommentAuthorWill Jagy
    • CommentTimeDec 7th 2011 edited
    I got an answer at

    Our OP posted first on stackoverflow, got an incomplete answer, and guessed that MO was the logical next place. Some of his attitude was surely the fact that he had, indeed, asked some "applied" people first. If he had guessed that stats.stackexchange would be the best second choice, at the very least all the acronyms would have been recognized immediately (well, the svm one, I suppose I don't know about the radio one). It is then 50/50 whether they would have been willing to work with the OP to improve the question. It is just as likely the question would have been ignored. I don't see any closed questions there at all.

    Excellent, my AdaBoost guy also got an answer, =-=-=-=-=-= it just took two days. So some patience is part of it.