Recently deleted questions invisible

Question

In the past week, it has happened twice that questions I have answered have been deleted, but I was unable to see them in the moderator tools. One question I was able to find (and attempt to undelete) via my cell phone, the other is still missing.

What is happening? Is this a bug or a feature?

In particular, a few hours ago I answered an interesting question about the density of regular languages containing the language of all squares. Now the question has vanished from sight, and I am unable to find any mention on it, although I both edited it and answered it. I suspect that this was a homework question, and the OP wanted to hide the fact that they got the answer on the web.

This kind of behavior is unacceptable, and I am especially disheartened by the stackexchange platform cooperating with it. Should I open a dummy account and upvote all my answers to prevent them from being deleted?

As a concrete feature, if a question I answered got deleted, shouldn't I, at the very least, get notified so that I can vote to undelete it?

Answer 1

This has come up before, so I'm not going to repeat what I wrote the last times:

• Self-deleted questions
• Another self-deleted question

There hasn't been any change in the Stack Exchange software. Askers can unilaterally delete their question if it has at most one answer and that answer has no upvote.

As a reminder, our policy is that moderators undelete questions that were self-deleted if they have an answer with lasting value. But I'm afraid moderators can only help when we're made aware of a specific case, because we don't have good tools for oversight. The only way to find out about these deletions is to look at the “recently deleted answers” page linked at the bottom of the “Answers” tab on your profile.

I've undeleted Infinite sequence has $m$ consecutive digits – regular languages and Density of regular language containing all squares