Suppose you come across a question that has been closed for lack of context, has high quality answers, and on its way to being deleted. Can you save the post by editing it to include more context?
Here is the deciding question:
Can the question be salvaged without changing the author's intent?
So, what are some things you could do?
You can fix or add MathJax.
You can clarify the author's English or phrasing.
You can add in relevant definitions, theorems, or simple background and motivation.
You can add a source for the question.
You can add context which was provided by the original author in the comments.
Now let's look at a few examples of actions that would change the author's intent.
Do not add an attempt. Adding an attempt modifies the author's intent by adding presumed information about their background, prior knowledge, mistakes or lack thereof in earlier parts of the question, and their understanding of mathematics in general.
Do not expand the question with so much context that it changes fundamentally. Doing so modifies the author's intent by presuming the author's level of sophistication and mathematical maturity.
Some might be thinking, "But what if the latter types of edits produce a great question?"
Well, yes. It is undeniable that one can write a great question by removing enough of a bad question and adding enough good. And math.se needs more great questions! However, we don't want to get into a ship of Theseus situation here. With few exceptions, a question should primarily remain the product of its author, while being helped and improved by editors, not commandeered by editors.
So, how can one save a question that can't be salvaged without changing the author's intent?
If the question is unsalvageable, you can rewrite it entirely by posting a new question. Here is the procedure:
Ask a new question that does include proper context. The new question must be well above what would normally be the bar for acceptability. It must be well-written, including background, motivation, source if applicable (especially for contest-math), etc. In particular, the context in the new question should not be an "attempt." If you're unable to formulate the question with context that is not an attempt, then the question is not valuable enough to be saved.
Leave a comment on the question stating your intent to rewrite their question.
Wait for 7 days. This gives the OP an opportunity to object to the rewrite.
Flag for the answers to be merged into the new question.
Q: Which questions can be saved via a rewrite?
First, let me stress two points:
Most questions do not need to be saved.
Most questions that can be saved are salvageable through edits.
It is crucial to note that the rewrite process uses moderator resources, which are a limited commodity. Therefore, to qualify for a rewrite merge:
The original question must have at least one high quality answer.
The new version must have meaningful, distinct substance from what is contained in the original, and provide notable value to future users.
Furthermore, at least one of the following must be true:
The original is in direct risk of deletion, or has been subject to a delete/undelete war in the last 90 days.
The original predates the new context standards (i.e., was asked prior to 2015).
Q: What do I say in the comment warning the user that the question will be rewritten and merged?
Link this post and the context section of How to ask a good question.
I have rewritten your question to include context pursuant to the rewrite guidelines. I have flagged this question to be merged with the new question in seven days. If you would prefer to edit context into your question yourself, please raise a flag before that time so that the merge may be delayed or cancelled.
Source for copy-paste:
I have rewritten your question to include
[context](https://math.meta.stackexchange.com/a/9960) pursuant to the
[rewrite guidelines](https://math.meta.stackexchange.com/q/32402).
I have flagged this question to be
[merged](https://meta.stackexchange.com/q/158066/) with the
[new question](https://math.stackexchange.com/q/$FOO) in seven days. If you would
prefer to edit context into your question yourself, **please raise a flag**
before that time so that the merge may be delayed or cancelled.
(Make sure to replace $FOO with the appropriate link.)
Q: Should rewritten questions be Community Wiki?
No. Community wiki isn't a tool for reputation denial.
Q: My question has been rewritten and I don't like the new version. What can I do?
Edit proper context into your question prior to the merge date. If you need more time, raise a flag on your question (the original) requesting the merge be postponed. If the question has already been merged, this cannot be undone.
Q: What sort of context can be edited into a question?
The new question ought to contain motivation for the question and canonical background such as relevant definitions and theorems. In the case of textbook problems, it is a plus to add a citation to the source; in the case of contest math questions, this is a requirement.
Regardless of whether you are rewriting the question or editing context into the original question, do not simply add an "attempt". In the case of editing context into someone else's question, adding an attempt changes the intent of the author, so it is disallowed. Posting a new question that includes an attempt will make it so we do not consider it a "rewrite" and thus it will not be eligible for merging, and will also be open to being closed as a duplicate.
Q: When editing a question, should I signal that the parts that I add come from me and not the OP?
No. We have revision history for that. In particular, don't use forum-like syntax such as "EDIT:" or "ADDED BY {your name}:" Each version of a post should read as though it was posted by a single author in its current form.
Q: When is it appropriate to rewrite a question vs. edit context into the original question?
Qualitatively, edit context into a question if it is salvageable, and rewrite only if the question absolutely cannot be salvaged.
To elaborate on this, there are many "solve my problem" questions which no amount of editing can save. However, a new question might put the particular problem into a broader context, so that the original question becomes an abstract duplicate of the new question. If this can be accomplished while preserving the integrity of the original answers, merging them in improves future value of the question to other users, which can then serve as a duplicate target for similar questions.
