3:11 AM
in Math Meta Chat, 17 hours ago, by ryang
https://math.stackexchange.com/tags/synonyms <--- I just noticed that the tag "first-order logic" has just been made the target for the tag "predicate logic" (under 40mins ago), but I can't figure out who was responsible for this or even how to vote for such things. Previously, the two tags had different scopes (FOL leaned more towards formal proofs, while PL was less rigorous). Can I vote to reverse this tag synonymisation?
in Math Meta Chat, 2 hours ago, by Xander Henderson
@ryang As far as I can tell, the synonym has existed since 2018.
in Math Meta Chat, 33 mins ago, by ryang
hi @XanderHenderson According to the link I provided, about 40minutes before my previous comment, FOL was made a tag target of PL; I noticed this because I was (trying to) add the PL tag to one Question Post (and the system did not immediately reject it at all) then noticed that clicking 'Submit' immediately retagged 'PL' into 'FOL'; I've also just noticed that this change is (by design) retrospective: every question previously carrying the PL tag now carries the FOL tag instead.
in Math Meta Chat, 29 mins ago, by ryang
How to vote to undo this change, that is, to retain PL as separate from FOL? On a separate note: I'm not sure either than that retrospective change can actually be undone (that is, can the system remember which Question posts used to carry the PL tag, now that it has already retrospectively conflated both PL and FOL into just FOL).

1 hour later…
4:13 AM
0

I need to prove the following The variation $|\mu|$ of a complex measure $\mu$ is finitely additive. The following is my attempt. Basically, my idea is to prove that $|\mu|(B_1\bigcup B_2)=|\mu|(B_1)+|\mu|(B_2)$ holds for any disjoint $\mathscr{A}$-measurable sets $B_1$ and $B_2$. I would reall...

2 hours later…
6:35 AM
To the best of my knowledge, only moderators can cancel the synonym. (I suppose discussion on meta typically precedes such a decision.)
After the removal, some manual retagging will be needed.
The synonym $\to$ was suggested in August 2018 and approved in December 2023: data.stackexchange.com/math/query/1178483/…
It was done by voting of users - without involvement of a moderator. So it seems likely that the two tags haven't been merged?
So they definitely haven't been merged.
For example, you can see that this question still shows both tags:
1

I’m taking my first course in real analysis, and I’m trying to prove the following proposition. Proposition: If $f:S\to\mathbb{R}$ is uniformly continuous, then $f$ is continuous. In comparing seemingly similar definitions of continuity and uniform continuity, I noticed that the only difference i...

in Math Meta Chat, 44 secs ago, by Martin Sleziak
@ryang I left a few comments in the tagging chatroom.
in Math Meta Chat, 18 secs ago, by Martin Sleziak
Since the two tags haven't been merged, at least the questions that haven't been edited since December 2023 should still have the original tags.
7:10 AM
@MartinSleziak Thanks for the investigation. So, it appears that I was mistaken about two things: (a) the 40minutes ago incident that I mentioned was the post I was editing to PL tag being renamed to FOL tag, RATHER THAN the point of creation of the tag target/synonym;
(b) my claim "every question previously carrying the PL tag now carries the FOL tag instead" is false, and I'd thought so because when trying to filter out the PL results on the MSE site the site immediately misleadingly renames the query to FOL instead and returns only FOL results.
To summarise clearly: the old PL posts have not been automatically retagged, however any new tagging attempt that involves PL (either with PL just peripherally as a bystander or any attempt to tag a page as PL) will result in its immediate synonymisation to FOL.
Isn't this state of affairs half-hearted? Instead, it feels more consistent/fair to Either merge PL and FOL, Or decommission FOL as PL's tag target.
P.S. "old PL posts" meaning "pre-2024 PL posts".
Well, this is basically how the synonym works.
It's up to the moderators whether they decide to merge the tags. Since merging is not reversible, some caution is needed.
Since you seem to be against the synonym, you should prefer the fact that the tags haven't been merged. (Otherwise the only way to restore the old tags would be by manual retagging.)
Nov 21, 2023 at 13:26, by Martin Sleziak
Pending tag synonyms: SEDE, list on site - when viewing this list, only the synonyms where users has score >=5 in the master tag are shown.
You mentioned that you do not know " how to vote for such things". If you go to list of the pending synonyms, you should see the ones where you can vote.
Naturally, you can also have a look at the FAQ - linked in the tag-info. But perhaps me and other users might be able explain some things relatively quickly.
You're right in saying that now - since the synonym exists - whenever someone tries to add to a question, it is automatically changed to . The same replacement is done whenever a question tagged is edited.

5 hours later…
12:11 PM
@ryang Feel free to ping me if some aspects of the system around tag-synonyms and related things (voting for synonyms, merging) needs a more detailed explanation.
If I am available, I'll try to respond.
12:58 PM
Thanks, Martin. I guess I have just one question (sorry to be thick): is it possible to vote to undo this tag targeting?
1:09 PM
While the tag synonym is pending you can vote against the synonym.
> Users with more than 2500 reputation and a total answer score of 5 or more on the tag, can suggest tag synonyms. Users with a total answer score (total upvotes minus total downvotes) of 5 or more on the tag, can vote for tag synonyms. Suggestions will be automatically approved when they reach a score of 4, and automatically deleted when they reach a score of -2.
But in this case, the tag synonym has already been approved. So you don't have an option in the system to vote against it. (It can only be removed by the moderators.)
Probably a reasonable thing to do if you think that some tag synonym should be removed is to make a question on meta about the tag synonym. (With an explanation why you think it should be removed.)
I suppose @XanderHenderson might correct me if something I wrote above is wrong.
The FAQ post has a section named: "How can I delete/reverse/undo bad tag synonyms?"
> Only moderators can correct bad synonyms. Therefore, the only recourse is to post a question on your per-site meta explaining the problem with the synonym relationship. Use the tags described above. Give the community a few days to show support or make alternate proposals.
> Once the discussion has settled, a moderator will perform the correction the community deems necessary. (If there is no moderator response a couple of days after clear community consensus is established, contact a moderator in chat or flag the meta post for moderator attention.)
> As the original tag that was added as synonym is not deleted but is simply hidden through the redirect to the master tag, deleting the synonym will restore the original tag page including the tag wiki and all other information. Questions which have been asked or edited in the meantime will be tagged with the master tag though, so manual effort is required to retag those when a synonym is removed.
1:24 PM
It seems to me that this needs to be discussed on meta. The tools I have tell me that the tag synonym was created in 2018, and "renamed" yesterday (I don't really know what that means). It is very hard to track the history of tags. :/
1:37 PM
The 2018 you're talking about is when the tag synonym was proposed.
It was actually approved in December 2023. (By enough users voting for the tag synonym.)
After all, this question was posted on 2023-12-04: Uniform continuity and the order of quantifiers.
Since it carries both tags, clearly the tag synonym wasn't active at the time.
The SEDE query lists 2023-12-05 as ApprovalDate.
7

What is the difference between the tags first-order-logic and predicate-logic? This question has been raised several times (here, here and here), and several users proposed in their comments to synonymize (or merge) them, but nobody concretely suggested them as synonymous on Mathematics. T...

These tags were discussed a bit in 2013:
3

Would it be justified to synonymize first-order-logic and predicate-logic (both ~100 questions)? first-order-logic as the primary tag seems sensible to me.

14

Having just been annoyed (ok, ok, I'm an old grouch) for the $n$-th time by seeing a question mis-tagged (indeed, mis-titled) propositional-calculus, I've just realized there is no appropriate tag for questions that concern predicate logic, predicate calculus, quantificational logic, first-order ...

@XanderHenderson I suppose "renamed" means that somebody entered and it was changed to by the system. See also: What does "renames" mean in the list of tag synonyms?
2:04 PM
0

The equation $x^5 - 2x^4 - 1 = 0$ has five complex roots $a, b, c, d, e$ . Find the value of $\frac{1}{a^8} + \frac{1}{b^8} + \frac{1}{c^8} + \frac{1}{d^8} + \frac{1}{e^8}$ . I know so far Newton's identity can be used to find power sum of roots if the power is non negative but no idea what to ...

0

Find all real roots of the irrational equation $\sqrt{3x^2+x-1} + \sqrt{x^2-2x-3} = \sqrt{3x^2+3x+5} + \sqrt{x^2+3}$ . My try : Given, $\sqrt{3x^2+x-1} + \sqrt{x^2-2x-3} = \sqrt{3x^2+3x+5} + \sqrt{x^2+3}$ . Let $u = x^2-2x-3, v = 3x^2+3x+5, w = x^2 + 3$ . Then, $3x^2+x-1 = u + v - w$ . So, the ...

I guess was just a typo - the question mentions Chebotarev density theorem: math.stackexchange.com/posts/4931750/revisions
2:22 PM
The tag was actually created and removed before: chat.stackexchange.com/…
9

Resolved. All occurrences of the tag have been removed. I suggest to remove theory-of-equations tag. This tag was created in December. The tag creator also provided the tag-excerpt and the tag-wiki which more-or-less follow the Wikipedia article Theory of equations. Looking at the tag-info,...