• I am baffled by the votes to close. How is this question inappropriate for meta? – Eric Wofsey Mar 23 '14 at 0:28
• @EricWofsey I bet one or both of the two people who voted to close this question are among the people who voted to close the question in the main. – Makoto Kato Mar 23 '14 at 1:14
• @EricWofsey : I voted to close because of the many previous meta threads about related matters that the OP has started. They seem to always end badly. – Andy Putman Mar 23 '14 at 2:16
• By the way, another reason for closing the question is that we do not allow cross-posting between math.se and MO unless a question has gone unanswered on math.se for a significant length of time (e.g. a couple of weeks). – Andy Putman Mar 23 '14 at 3:04
• @AndyPutman re your last comment. This is an overstatement in my opinion. (This is a general remark; I do not wish to defend the question.) – user9072 Mar 23 '14 at 15:20
• @AndyPutman [I voted to close because of the many previous meta threads about related matters that the OP has started. They seem to always end badly.] Are you saying that my meta question should be closed automatically whatever it is in this site? – Makoto Kato Mar 23 '14 at 22:56
• Wow, I should really visit math overflow more often. The same user has posted at least six similar "Why is my question closed?" in math.stackexchange.meta . Despite requests to refrain from doing this so much, it looks like it goes on. – rschwieb Mar 25 '14 at 17:28
• @rschwieb Asking the reason for the closure of a main thread in the meta is perfectly legitimate. I have no idea why some people object to it. – Makoto Kato Mar 25 '14 at 18:08
• @Makoto: Asking to try one piece of candy, to make sure you'll like it is not a problem. To just sit in the store and ask for more and more candy will get you kicked out. Stop insisting that whatever is fine "once" is fine "repeatedly, incessantly, and without self control". – Asaf Karagila Mar 25 '14 at 19:05
• @MakotoKato For the third time, nobody is claiming a question like this is illegitimate. Rather, this is about repeatedly ignoring community requests to stop doing it so frequently. Please note the difference. – rschwieb Mar 25 '14 at 20:12
• @rschwieb If you think it's legitimate, why do you request me to stop it? – Makoto Kato Mar 25 '14 at 20:23
• @MakotoKato You are still confusing two things. I do not think repeatedly ignoring the community's advice about the frequency of such posts is legitimate. – rschwieb Mar 25 '14 at 20:24
• @rschwieb Why does the frequency matter if each one is legitimate? – Makoto Kato Mar 25 '14 at 21:12
• "Why does the frequency matter if each one is legitimate?" ARE YOU SERIOUS? I used to give you at least some benefit of the doubt that you're not intentionally obtuse. I'm very happy to announce that I will not make this mistake ever again, you troll you. – Asaf Karagila Mar 25 '14 at 21:28
• @AsafKaragila I have no idea why you think that a meta question asking for the reason of the closure of a main thread is a troll. If the main thread clearly deserves the closure, it may be a troll. But it is not the case at all. – Makoto Kato Mar 28 '14 at 3:45

Your question was: "I would like to know examples of closed subschemes of $X$ other than $Z_n$", and when examples were given in the comments, you rejected them as trivial. Rather than explaining yourself further, e.g., describing why the examples were trivial, you repeatedly asked whether abx knows "what $Z_n$ means". You changed the question to include the condition that the underlying subspace is $Z$, but rejected Moret-Bailly's suggested answer as trivial.

Despite all of the comments, you still haven't explained why the non-projective property of the variety makes the question non-trivial (or rather, what it is about the projective property makes the question trivial). It is not constructive to declare that something is trivial without explaining why!

Based on this behavior, I think it is reasonable to conclude that you are unlikely to refine the question to the point where it admits a precise answer in the near future.

• I look forward to seeing this answer accepted! :-) – Scott Morrison Mar 23 '14 at 2:59
• I think a trouble is that no one has any clear idea what sort of answer would satisfy you. I have noticed that many of the threads you introduce have this character, where people offer various answers that are sensible but which are invariably rejected for one reason or another. This is frustrating and tends to erode the feeling that questions are being asked in good faith. Hence the reason for closure: "unclear what is being asked". – Todd Trimble Mar 23 '14 at 4:59
• I accepted Moret-Bailly's example. – Makoto Kato Mar 23 '14 at 9:04
• @ToddTrimble [I think a trouble is that no one has any clear idea what sort of answer would satisfy you.} I'm asking examples of closed irreducible subschemes of a complete non-projective non-singular variety whose underlying subspace is $Z$, other than $Z_n$. What's so difficult to understand this? I also said the more examples, the better, which means that I'm asking a big list of examples. Asking a big list of examples is not allowed here? – Makoto Kato Mar 23 '14 at 9:05
• You rejected abx's answer which mentioned infinitely many examples because they are "essentially one". You then told abx that he/she obviously didn't understand the question. That word "essentially" doesn't make the intended question any easier to understand; one has to guess what you consider "essentially different", and also how many "essentially different" examples are required to satisfy you. Two? Three? More than ten? (To your rhetorical question: "big list" questions are allowed, but they work best when the recipient is happy to hear the answers and gives thanks instead of objections.) – Todd Trimble Mar 23 '14 at 12:37
• @ToddTrimble If I don't misunderstand his answer, his curve is reduced. So it does not satisfy the condition of the question. – Makoto Kato Mar 23 '14 at 16:58
• Since people continue to upvote this answer, I repeat I ACCEPTED Moret-Bailly's example. – Makoto Kato Mar 25 '14 at 20:56