Sorry to take your conversion a bit off-topic, but what do you guys think about reopening Is it best to run or walk in the rain? It there any dispute that there is plenty of hard math in certain optimization questions related to moving 3D shapes?

I feel like quoting Peter Lax, in his acceptance speech for the Abel prize:

Traditionally mathematics is divided into two kinds: pure and applied. The relation of the two is delicate. The great applied mathematician Joe Keller's definition is: pure mathematics is a branch of applied mathematics. He meant that mathematics, beginning with Newton, was originally concerned with answering question in physics, it is only later that the tools and concepts used were elaborated into theories that took on lives of their own.

If we take that point of view seriously, if we disallow applied mathematics then pure mathematics goes too. But I am all for applying strict standards; either the question or any likely answers should contain real mathematics, and merely asking us to turn a vague non-mathematical question into a mathematical one is unacceptable. The questioner should be expected to do his own hard work. But I think it should be okay to ask, say, what models of granular flow generate interesting mathematics. Given the crowd that usually hangs out at MO, there may not be many useful answers, but that might change, and I don't think it's right to scare away the people who want to discuss such issues.

I happen to be better qualified to judge "pure" questions than applied questions in most cases, and there are still only a handful of 3000+ reputation users, so if there is a question that doesn't look like a good question to me, but I'm not absolutely sure, I'd rather close it (and reopen it later if it turns out I was wrong) than let it slide, setting the precedent that poor questions are acceptable. I don't have a problem with people saying that the moderators at MO are a bit trigger-happy with closing questions, but that they are fair-minded and will reopen the question if you make a good case. It's more important to me to keep the quality of the material high than to be super welcoming.

That said, I (almost) always leave a comment (or vote up a comment) explaining why I've downvoted or closed a question. If I can't put into words what's wrong with the question, then there is likely nothing wrong with it. I don't think I'm putting topics outside my areas of interest at very much of a disadvantage with this strategy. I agree that it's a shame that some areas are so poorly represented.

@Ilya: obviously I'm not going to vote to reopen my own question, I think that would be an abuse of privileges. Why don't you vote to reopen and see what happens?

I notice that Tom Leinster has expanded on his reaction. I have some sympathy for his point of view; I would argue, though, that I think that this particular subject comes up more often than most and that as professional mathematicians we should be aware of ways to sell our subject - but maybe that's an argument for a single meta-question rather than lots of little ones. I also tried quite hard to ensure that the question was focussed and had a possible answer that didn't involve going in to all the details of the mathematics of walking in the rain.

One slightly bizarre reason for reopening it would be to allow it to sink down in the morass. I think that the fact that it was closed has kept it further up the "active" list than if it had merely been answered and forgotten. If I'm reading the reputation scores correctly, then it is currently 11-4 in favour, with 2 favourites. I suspect that if it hadn't been closed, it wouldn't have gotten half of those votes.

More generally, I'm not in favour of closing questions that turn out afterwards to not have a good answer. I think that closing a question sends the message that this shouldn't have been asked. Slightly more borderline is the type of question that shouldn't have been asked in that way (the one on Badiou and Mathematics springs to mind); I would still vote to close these but with a "revise and resubmit" comment. But closing a question just because it turns out later to have been a daft question sends the wrong message, I think. I like to keep in mind the following quote about working for Pauli:

It was absolutely marvellous working for Pauli. You could ask him anything. There was no worry that he would think a particular question was stupid, since he thought all questions were stupid.

@fpqc, are you also for holding everybody to high standards for politeness and tolerance? ... ;-)

Sure, but there's no reason to be impolite to people who you perceive to not have displayed enough premeditation and thoughtfulness.

Being impolite is essentially never humorous, at least where I come from. That said, in non-academic social circles I often feel left out by my inability to "put someone down" in a "funny" way...

@Anton: my main problem with that is that I don't know who are the right people to email. If I did, I'd just send them the question directly.

I don't know enough information about your particular questions, but I'd like to say that questions can be closed for many reasons, for example, for being outside the core competency of people on MathOverflow.

Thus, even a very well-written and interesting question is likely to get closed if its main topic is far enough from pure math to suggest that the experts in this particular question would be concentrated in other places.

The questions within the core competency of mathematicians, that is, mathematical questions, are sometimes vague, like, indeed, many questions about K-theory. But it's often immediately clear for the person who worked on K-theory what the question is, even if it is sloppily written, poorly thought or contains incorrect statements.

This is the way community works — and I don't think I have an easier way to formulate what types of questions will be welcomed by voters and moderators than "they should be interesting to mathematicians". Perhaps somebody will be able to explain it better than me.

Apologies; my post must have been unclear, since I intended to include numerical analysts and other people with math competencies which may be currently under-represented into the "community" and "people on Math Overflow".

Let me give an example of question that I would consider a good candidate for closing as "good, but doesn't belong here": a question asking to write a good code in a specific programming language to solve a specific math program. Those questions will find a rich base of highly competent people to discuss it on Stack Overflow.

Here's a specific example which in my opinion is very well-suited for StackOverflow (where it was posted).

I was an active participant of Stack Overflow before I found Math Overflow, and I would really like to answer the above question. But I've come to realize that the best thing to do if such a question is posted on MO is to "transport" it somehow to SO. For example, it doesn't really fit the "arXiv+" classification scheme.

Again, my post was not intended to convey any more complicated thoughts than the observation above.