@A---B I am sorry that it took me quite a long time - I am rather busy these days. But I have finally posted a question on meta about this issue: Do some calculus theorems deserve to have their own tag?

A new tag: einstein-summation.

@MartinSleziak Thank you very much for the question.

We will see what other users say about this. (Although quite often there is a very little interest in tag-related questions on meta, so it is possible the the question will get no answer.)

It is probably clear from our previous interactions that I consider these tag too narrow/too specific. But if the discussion shows that the Math.SE community supports the idea of such tags, I have no problem to tag along.

Yes I do understand what you mean. I created some of the tags by mistake.

^ Occasionally I try to make a joke or a pun, but since English is not my first language, I am not sure whether I really succeeded with tag along. :-)

I think you succeeded this time. I thought that was a coincidence.

So I did not point that.

@MartinSleziak Are there some rules about creating new tags ? I will take care next time.

I would not say that there are hard rules, probably mainly common sense and experience with tagging system. (Seeing some past discussion about creating tags and tag-synonyms probably helps.)

If you want to read a bit about this you can look at some posts on meta related to this issue.

For example, New Tags: When? and How liberally should we handle tag creation?

This one might also be of interest: Should every new tag be discussed on meta before creation?

But briefly said, if you are not sure whether or not create a tag, probably the best way to go is to propose creation of the tag in the tag management thread on meta.

In this way there is a chance that you get some feedback from other users. And if the reaction is positive, then you can go ahead and create the tag.

@A---B Why not posting this as an answer to the question I posted. In that way you will get feedback from more users.

But you should certainly add some details when posting the answer. (At least list some of the theorems which you think should be included there.)

I agree that Rolle's theorem, Mean value theorem and perhaps also Intermediate value theorem have somewhat similar feel and they are certainly related to each other. Although I do not know whether there is some name which is commonly used for this group of related theorems.

"Continuity-theorems" ?

But that is an advantage of making post on meta - if some users have idea for a better name (or an alternative name) for this tag; they can post such suggestions in comments.

Personally I liked value theorems better. But you can mention several suggestion in the post on meta - and also explicitly ask other users to make other suggestions in comments if they have idea for a better name.

Yes I will in evening. I have some work currently.

Do you run a script or something like that in this chat room ? How did mange it so well ?

I guess you have been around long enough to know this, but I will just remind you that voting is different on meta. So if your answer receives some downvotes, that does not mean that it is a bad answer - voting simply helps to show whether users support the proposal or are against it.

@A---B The only automated thing here is the feed which posts here all questions tagged taggin or tag-management.

Yes I know that but I still feel bad when down voted.

I'll have to go AFK for some time now. See you later and have a nice day!

@MartinSleziak A last thing, my flag on question : math.stackexchange.com/questions/2170494/… was declined. What do you think should not the question be closed for not showing any work ?

Yes have a fine day. Nice to talk to you :).

@A---B Did you flag it as off-topic? Or some other kind of flag?

If it was flagged as off-topic, the reason that it was declined might be that in the review the users voted to leave open. However I am not sure about this.

Probably better place to ask about flags is Math Mods' Office. That room is visited by moderators and some other users which are rather experienced and know more about flag.

Here is somewhat similar question on meta: Declined question flag. Probably you can find more related discussions on meta.

One more comment about the tags - I would consider a tag for group of theorems less objectionable than having individual tags for, say, Rolle's theorem, Mean value theorem, Intermediate value theorem. (Still I'll have to think about this a bit more. And we will see what also the reaction of other users when you post an answer on meta.)

There was also some brief discussion related to the above question (tags for calculus theorems) in another chat room.