Another time recently, an user has asked a question which is very far from research level, and has been reprimanded for not reading the FAQ. However, I realize that there might be a problem in the formulation in https://mathoverflow.net/help/on-topic:
MathOverflow's primary goal is for users to ask and answer research level math questions, the sorts of questions you come across when you're writing or reading articles or graduate level books.
Let's just put ourselves in the shoes of a researcher in a very applied area of statistics and economics. Matrices aren't really their cup of tea, and reading a paper they have come across a really unusual (for them) manipulation such as the one in my example question. So they google around, and they find this forum and the above help page. Then they think:
- Is my question a math question? Sure!
- is my question research-level? Of course, I am doing research. Just not research in maths, but in my own field. It's exactly "the sort of questions you come across when you're writing or reading articles".
So why should it be off-topic?
I am not claiming that this sort of questions should be on-topic here; I am just saying that our help center does not do a good job of explaining to a new user what sorts of questions are welcome here. It seems to me like the rest of the page does not clarify this matter any further than the sentence I have cited.
There might be a subtle point on whether research level math questions here means research level questions about mathematics or questions about research-level mathematics, but we shouldn't expect a non-native English speaker to grasp it.
I think we should change that sentence in the help center, not to mislead new users.