6:06 AM
To me the most relevant tags for questions about limit superior of sets seem to be and . (The latter is explicitly mentioned in the tag-info.
So here I removed and to replace them with these two tags. (And maybe even some other tags which this question has could be safely removed...?)
5

This is a question on what is written here. If $A_i$ is a sequence of sets, define$$\liminf_i A_i = \bigcup_{j = 1}^\infty \bigcap_{i = j}^\infty A_i, \quad \limsup_i A_i = \bigcap_{j = 1}^\infty \bigcup_{i = j}^\infty A_i.$$What is an example where $\liminf_i A_i \neq \limsup_i A_i$? Take ...

4 hours later…
10:01 AM
Do we really need tag?
0

I need to find the number of 3 digit numbers without repetition (distinct digits). MY ATTEMPT: All 3-digit numbers:$100,101,102,103,.....,999$ (i.e. $1000$ numbers) But we need to exclude following types of numbers _11,_22,_33,..._99 type (8*9 numbers = 72 numbers because the first digit sh...

I have removed it. We will see whether there will be objections from the tag creator (or somebody else).
I have added , the tag-info explicitly mentions identifying errors.
BTW now that there is a synonym $\to$ , shouldn't the tag-wiki also reflect that it is not only about proofs?
It seems that the old solution verification tag-wiki only contained one sentence in the tag-excerpt: "For posts looking for feedback or verification of a proposed solution."
BTW the tag-wiki for the synonymized/deleted tag can be found using this query.
0

Some time ago the synonym solution-verification$\to$proof-verification was created. (The synonym itself was discussed here, I'd say that without reaching consensus. And to me also it does not seem entirely clear what is better choice for the master tag. But anyway, the synonym exists.) But after...

1 hour later…
11:40 AM
I think that question like this appears quite often. And probably the tag might make it easier to find the question in the future. I am not sure which of the 5 tags to omit. Perhaps -- it is a very big umbrella tag?
14

Prove that $$\sum^{n}_{i=1}\binom{n}{i}i=n2^{n-1}$$ I can't find counting interpretations for either of the sides. A hint of "if $S$ is a subset of $\{1, . . . , n\}$ and $S^\prime$ is its complement then $|S| + |S^\prime| = n$" was also given, but I still don't know how to begin.

12:12 PM
The tag-info for seems to indicate that it is for subspaces of vector spaces. Perhaps a more descriptive name for the tag would be suitable?
I was hesitating whether to add this to this question: Closed Subspace of a Banach Space with a Non-closed Linear Complement. But, after all, normed spaces are vector spaces, so I added it.
Indeed, the problem was mentioned a few times.
The answer suggesting removal of the tag is at +6:
6

There's another possibility that hasn't been mentioned in the OP, and the one I would prefer: kill it! I don't see subspaces as a tag that will ever be consistently used, and not something that has a concrete enough meaning to allow for an easy delineation of when it should be used. Should you a...

It seems that there are only a few questions which have only this tag.
I have added the information that this tag now has tag-info to the question. Since the question has been bumped, this mind remind other users that there is a problem with this tag.

6 hours later…
6:22 PM
0

I see a lot of interesting questions, broadly in the category of contest math and recreational math, about the base $b$ expansion of an integer, often $b = 10$. For example: the sum of the digits, when this expansion has repeated digits, how many $0$s at the end, and so on. I would like a tag to...

4 hours later…
9:53 PM
3 more questions in tag:
-2

Im having some problems isolating $\sigma$ in this expression: $$2\eta/ \sigma=A_1(\sigma/\mu)^{n_1} exp(-C_1)+A_2(\sigma/\mu)^{n_2} (b/d)^m exp(-C_2)$$ Maybe someone can help me! Thanks in advance.

-2

$$x + \frac{5} {2} = \frac{1} {6}$$ $$6 ( x + \frac{5} {2} ) = 6 ( \frac{1}{ 6})$$ $$3 ( x + 5 ) = 1$$ $$3x + 15 = 1$$ $$3x = -14$$ Why is it that we do that?

0

I was reading Wikipedia and came across the equation $e^Tx^2 + \frac{1}{T}xy + \sin(T)z-2=0$ and Wikipedia says that it is not a polynomial equation in the four variables $x,y,z$ and $T$ over the rational numbers(since sine, exponentiation, and $\frac{1}{T}$ aren't polynomial functions). However,...

In addition the 3 question previously mentioned here.
0

The tag variables has been created recently. (The list of new tags says that (variables) was created Sep 5 at 9:04. So most likely in this question.) At the moment, there are 6 questions with this tag. The tag-info is empty and I have difficulties to imagine consistent usage of this tag. So I su...