I have noticed a chatroom called Mathematics. The transcript starts on 12 September 2014.

It is unusual in several aspects:

  • The first day of transcript shows similar messages which are shown in the "main" chatroom - many sites have a room that was created together with creation of the site. ("Welcome to chat for: Mathematics This is a general discussion room, but please feel free to create more subject-specific rooms (a single room with every possible discussion isn't very helpful). For playing with chat features Sandbox...") However, there are much older rooms associated with this site, including the one which the most users of Mathematics Stack Exchange use.
  • It seems that the room was never frozen, but it had no activity between August 2017 and May 2020. (According to the chat FAQ, a room is frozen after 14 days of inactivity; while several posts here on meta mention that one exception is that if the room is the sole room for a particular parent site, it isn't frozen, this isn't the case here.)
  • The logo in the room info says "Mathematics". But when I list the rooms associated with Mathematics Stack Exchange and sort them by recent activity, I do not see this room in the list.

Question. Why wasn't this chatroom frozen? Which site is it associated with?

I am asking partly out of curiosity. And partly because sometimes it might be useful to have a room which can never be frozen.

EDIT: Some other instances of sites that have two "main" chat rooms, one of them inactive:

EDIT2: Mithical's answer explains that this room is actually associated with chat.math.stackexchange.com. Sonic the Anonymous Hedgehog has created another room associated with chat.math.stackexchange.com. And the room mentioned above was eventually frozen.

  • 1
    Interestingly, it also has absolutely no Room Owners.
    – Mithical
    May 21, 2021 at 6:50
  • 6
    @Mithical not too weird. The room was created by what seems to be an automatic process, and in such cases, you'd have to meet the criteria here to be automatically appointed a room owner. The activity in there is way too low to get to that point.
    – Tinkeringbell Mod
    May 21, 2021 at 7:09
  • 1
    The room in question may end up getting frozen soon, as I just created another room parented to its same site. See Mithical's answer below. May 23, 2021 at 1:48
  • @SonictheAnonymousHedgehog Keep in mind that the new room needs at least some messages - in order to survive longer than 7 days. ("A room is considered worth retaining if it has more than 15 messages by at least 2 users. Rooms not worth retaining which are inactive for 7 days will be deleted. Rooms worth retaining which are inactive for 14 days will be frozen.") I have posted something into the "mysterious room" after posting this question, so there is some time before reaching 14 days of inactivity.
    – Martin
    May 23, 2021 at 4:24

1 Answer 1


It looks like somehow, the room isn't hosted on Mathematics.SE, but rather chat.Math.SE.

If you go to the "all rooms" button on that room, it takes you to https://chat.stackexchange.com/?tab=site&host=chat.math.stackexchange.com. To contrast, the same button in the main Math.SE room links to https://chat.stackexchange.com/?tab=site&host=math.stackexchange.com. Note that in the first example - the weird room - the site host is chat.math, and the regular room the host is just math.

Since it's probably the only room hosted directly on chat.math.stackexchange.com, it hasn't been frozen due to the rule that if there's only one unfrozen room hosted by a specific site, it can't be automatically frozen.

As for how it happened? I have no idea; looks like a bug.

  • 6
    Wait. Does math even ... have a chat server? May 21, 2021 at 6:55
  • 4
    @JourneymanGeek - I think it used to, back in the old days when the plan was for every site to have its own distinct chat server.
    – Mithical
    May 21, 2021 at 6:56
  • 2
    According to this balpha's answer, the chat.<site>.stackexchange.com was abandoned in January 2011 - the room seems to be newer than that. Good idea with trying "all rooms" - I did not think of that. (Although I've noticed that such link is also mentioned in your post from 2020: chat.<site> redirects are giving a server error.)
    – Martin
    May 21, 2021 at 7:06
  • 4
    So we have 4 chat servers?
    – rene
    May 21, 2021 at 7:07
  • 6
    I have a feeling that there was (still is?) an old piece of code written from before the move to merge all the separate chat servers into a single one, which is what triggered the bug here. May 21, 2021 at 7:49
  • 8
    Turns out, the system doesn't validate the field for parent sites. I was just able to create another room with chat.Math.SE as the parent site, by tweaking the page HTML. May 23, 2021 at 1:46
  • Just an additional observation from tinkering a bit; unlike normal rooms, which have a host field when editing the description, there's no such field on these rooms. presumably because the host site isn't considered a valid option. Jun 5, 2021 at 15:04

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