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7:37 AM
I continue with removal of the deprecated tag when such question is among recently active questions (i.e., new question or bumped). But sometimes I struggle to find a suitable top-level tag.
What is suitable tag for questions about semigroups? According to the tag-excerpt it should be , right? I wondered about this when retagging Semigroups containing an ideal with a local identity.
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Q: Semigroups containing an ideal with a local identity

M.H.HooshmandI'm looking for some classes of semigroups containing a (proper) ideal with a local identity (i.e., ideal submonoid). Can somebody give some examples or/and theorems for the followings cases: (a) Non-commutative and commutative semigroups with an ideal submonoid that is not an ideal subgroup (...

This question also reminds me of ideals tag. When we had discussion about the tag with the same name on Mathematics, the result was that it is used for all meanings (ideals in rings, set-theoretic/order-theoretic ideals, ideals in semigroups, etc.) See: math.meta.stackexchange.com/questions/4791/…
Was the tag discussed here on MO? (The tag-info is empty at the moment.) Should it be used similarly as on Math.SE? (I.e., does it include several meanings of the word ideal; ideals in rings, semigroups, set theory, ...?)
 
 
1 hour later…
9:05 AM
0
A: Help improve tagging!

Alexander ChervovThere was tag open-problems-list for questions asking list of open problemsin certain area or more generally satisfying certain criteria. But it disappeared recently. I do not think it is good. Can we revert it? There is tag "open-problem" but that tag is very general and there too many questi...

I suppose the tag have been merged by a moderator. (At least this is what it seems like when I look at a random question which used to have this tag, for example, Open problems/questions in representation theory and around?)
So if this should be changed back, probably the only solution is manual retagging.
The merge was probably done in the past few months.
Wayback Machine shows 42 questions in March 2017.
If the decision is not to create again, would retagging such questions using both and be a reasonable solution? Currently there are 20 questions tagged open-problems+big-list.
BTW when I said that the merge was done relatively recently, I should have also mentioned that this page which is still in Google Cache says that the tag still existed on 22 Aug 2017 (with 43 questions).
According to the Wayback Machine snapshot (from Match, with 42 questions) among the questions tagged , 17 were also tagged and 15 were also tagged .
The cached version gives similar numbers, 17 for and 16 for .
 

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