Confusing rolling back of edits by the moderator

Question

This recent question: Show that the $l_p$ norm of $x$ as $p\to 0$ is the support of $x$ was nominated to be reopened in meta after edits. It was then reopened by several other users.

Here is version 4 of the post before being nominated to be reopened:

This post has some trivial typos, and the context is clear to those who know the background of the topic. The asker was questioned by a user in a comment for context, and the asker did post a comment containing a link to the book, which clearly writes the needed relevant definitions. I edited the post using the asker's link twice, which led to version 6 of the post:

I have seen in many compressed sensing books (e.g. An Introduction to Compressed Sensing by Mathukumalli Vidyasagar) the following statement: $$\lim_{p\rightarrow 0+} \|x\|_p = \lim_{p\rightarrow 0+}\left(\sum^n_{i=1}|x_i|^p\right)^{1/p}=|\text{supp}\left(x\right)| $$ where $\textrm{supp}(x):=\{i:x_i\ne 0\}$ and $x\in\mathbb{C}^n$. (See, e.g., page 4 of the linked book.)

I have no idea how to prove it. I have seen various other questions and their corresponding answers but none clearly states a process to obtain the proof. Is there any book where a proof is given? How should one start this proof?

The mentioned comment containing the book link was then deleted. I do not know whether it is the asker or mod who did it, but it is now gone.

Moderator Xander Henderson, who closed the post together with another user previously, rolled back my edit to version 5, which had not contained the essential edit of correcting typos and adding the book link.

The moderator insists on the old version of the post and left a comment:

^{Please do not edit a question to introduce context or sources which were not originally given by the original asker. It would be reasonable to leave a comment to suggest a citation, but the content of the question needs to come from the original asker.}

He insisted that "It is the job of the asker to make those kinds of edits. "

I do not at all understand such rollback.

I do not want to have an editing war with the mod regarding this particular post. But I do want to ask for the community's opinions if the current version of the post is preferable.

Answer 1

Let me first get some trivialities out of the way : this question isn't a duplicate (as far as my research has gone, ref. my comment on the main thread) , it isn't broad, opinion-based or outside the scope of the site. The only criterion for closure is the lack-of-context one.

The general problem associated with context rewrites is either adding too little context, or creating a "Ship Of Theseus" situation (whereby the question doesn't belong to the original poster anymore, but is primarily the contribution of other users), or attempting to salvage a question that is closable for reasons apart from a lack-of-context. I have addressed the first one in my first paragraph.

I do not believe this edit, in any way, is a Ship Of Theseus situation. The now-deleted comment contained enough information to identify the source of the question (i.e. book and page number), and the edit computed this information and integrated this into the post, along with improving the MathJax. In no way can this be described as "hijacking" the post : the only judgement made by the editor is how to integrate the information and what "style" of MathJax should be used, all of which are fairly non-controversially performed, in my opinion.

The given question is salvageable because it isn't closable for any reason apart from lack-of-context and contains a fairly novel question, linked with a part of mathematics (Compressed sensing) which isn't explored much on Stack Exchange. Answerers may be tempted to add how the result is relevant in the given field, for the benefit of future visitors with the same context : something that isn't as common as , say, elementary number theory for example. In fact, if the moderator's edit is rolled back (I will do it if this answer is received well), I will attempt an answer.

All said and done, I believe I have provided enough justification for this question to fall within the jurisdiction of the Guidelines for Context Edit and Rewrites : the question is salvageable and novel, the edit is not a "Ship of Theseus" situation and is sufficient for reopening the question because it isn't closable for other reasons.

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I wanted to address the "teach a person to fish" argument and the OP-comments-to-context behaviors here as well , but that's got a small enough inner product with the main question, so I will prefer to discuss this in the comments below this answer.