Unless the dupe target contains exact question with exact same proof (without further generality), I'd recommend not closing as dupe. I know, it can be frustrating when one sees the same question many times. So, I propose going to the search and writing "-[solution-verification] closed:no" without quotes. This will make it so that all the solution verification questions are removed from your feed.
Don't close solution verification as dupe, instead remove questions with the tag of [solution-verification] appearing in search
Why many "solution-verification" questions are closed
As has been articulated many times in the past, the goal of Math SE is to create a library of questions and answers. A question should be of use and value to more than just the asker. The problem with solution-verification questions is that they are typically far to narrow to be of use to anyone except the asker.
What often happens is that someone will want someone to, essentially, check their homework for them. So they copy the problem into a question, then put their solution in and add the solution-verification tag, and ask that the community here vet their work. These questions are almost always far too local—they are useful to the asker, but to practically no one else.
This is a misuse of the tag, and these kinds of questions should be closed.
An appropriate use of the solution-verification tag is to ask a specific question about a single step in an argument. "Is my proof correct?" is not a good question for this site. "Is my use of Harnack's inequality justified in this step of my proof justified?" is a much better question. The tag wiki for the tag links to another meta question on solution-verification questions; one of the answers to that question gives a reasonable example of what a good question in this tag should look like.
Heuristically, questions which which come down to grading someone's homework are not appropriate for this site. If you are taking a class, your instructor or TA or grader is paid to do that job; if you are self-learning, there are other, more "social" sites out there where you can get help (including the Mathematics chat room here!). In the same what that Math SE should not be used to get other people to do your homework for you, Math SE should also not be used to get other people to grade your homework for you.
Why simply "ignoring" this tag doesn't work
As noted above, the goal here is to create a library. The primary audience of the site is not those people who are here everyday, who have tags that they are following, and who are simply scrolling the front page.
The primary audience consists of people who are coming to this site via searches (e.g. via Google, Bing, etc). Good question / answer sets here are going to be visible to search engines, and are not going to clutter up search results with redundant questions.
Certainly, users here can ignore certain tags, but this is not going to help with the problem of search results getting polluted with countless "grade my homework" questions. The goal of closing these kinds of questions as duplicates is to help the search engines to know which pages to display to users who very probably don't even have accounts here.
What makes a good "solution-verification" question (TL;DR version)
- Bad: Is my proof correct? (essentially, "grade my homework for me")
- Better: Is step [n ] of my solution justified?
- Best: I have applied [theorem] in step [n], but I am don't understand why the hypotheses of [theorem] are satisfied. Can you please help me understand why [theorem] applies in this case?
NB: This is not official moderation policy right now. This is my opinion about how this tag should be used, with my moderator hat off. However, policy on meta is determined by voting. As always, upvote to agree, downvote to disagree.