Talk:Orthogonal group/Rotation group (disambiguation)

Only one link to each article
What namely does WP:Manual of Style/Disambiguation pages say about the number of link to each article? Provide an exact citation, please. Redirects are also not discouraged on a valid pretext. I strongly suggest user:JohnBlackburne to consult WP:DABREDIR actually (2. the redirect could serve as an alternative name for the target article…) instead of waving various WP:three-letter-combination bludgeons. Incnis Mrsi (talk) 17:08, 22 January 2014 (UTC)


 * The point of disambiguation is to help readers find the article they want, by giving the most common name. Listing an article multiple times causes problems with this. First it looks like two articles, causing readers to be confused if they try one then the other, or follow special orthogonal group and find themselves at orthogonal group and think the link broken. Second it's simply clutter; the page should be as compact as possible, sometimes just bare article titles, and this includes including only one entry per article. I.e. looking at orthogonal group, general orthogonal group is also an alternative title (and redirect). Should that also have a line? Should other articles have lines for their alternate names such as U (1), SO (4)? No, as that would clutter the article with redundant extra links.-- JohnBlackburne wordsdeeds 17:44, 22 January 2014 (UTC)
 * To clutter what? As John said himself, we are in a disambiguation page, not in an article. The point of a disambiguation page is also to help editors, not only to help readers. To help fixing existing links, or to find targets for new links. The old version of a dab hid the two most important links that could translate a loose term “rotation group” into wiki:
 * Rotation (mathematics): in an unspecified context it perfectly can be rendered as “rotation group”,
 * Special orthogonal group: the only correct choice if the context assumes a Euclidean space, but of an unspecified dimension. I repeat: there are situations where this link is appropriate whereas “orthogonal group” would be confusing, so this “cluttering” is substantiated.
 * My edit also respected the rule “one line – one item”. There is such rule, and there isn’t any “one article – one line” rule. The “special orthogonal group” title marginally qualifies with WP:DABREDIR 1.: it indeed contain the word “group” and “special orthogonal” is virtually a hyponym for “rotation”, so we IMHO can ignore the literal requirement of 1. and proceed. Incnis Mrsi (talk) 18:47, 22 January 2014 (UTC)

Confusing list
The list, as it stands, is quite confusing, as some of the items are special cases of others. Here is it again, numbered for convenience:
 * 1) Circle group, the rotation group in two dimensions
 * 2) Rotation group SO(3), the rotation group in three dimensions
 * 3) Rotations in 4-dimensional Euclidean space, the group SO(4)
 * 4) Orthogonal group, the general rotation group
 * 5) A rotation group or proper symmetry group with fixed point
 * 6) Cyclic group, rotational symmetry group for an object with n-fold symmetry in a plane of rotation
 * 7) Point groups in three dimensions that are rotation groups

[1], [2], and [3] are all special cases of [4] (in 2, 3 and 4 dimensions, respectively). [4] is itself a special case of [5].

Moreover any [6] is a subgroup of [1], and any [7] is a subgroup of [2].

Ok, the article does not actually say otherwise. But for a reader who does not already know what all these groups are (and is maybe trying to find out), it could be more helpful. Maproom (talk) 17:56, 22 January 2014 (UTC)


 * It's a WP:disambiguation page, so is meant only to help readers find the article they want, out of articles with similar titles. It's not meant to contain lengthy or any explanation, just links to articles together with a few words of description to help disambiguate. That entries x and y are related is very common on disambiguation pages, perhaps especially with technical terms.-- JohnBlackburne wordsdeeds 18:09, 22 January 2014 (UTC)
 * My edit addressed exactly this problem. U(1), SO(3), and SO(4) are special orthogonal groups and my version makes it clear. Neither of them is an orthogonal group. Incnis Mrsi (talk) 18:47, 22 January 2014 (UTC)

Requested move

 * The following discussion is an archived discussion of a requested move. Please do not modify it. Subsequent comments should be made in a new section on the talk page. Editors desiring to contest the closing decision should consider a move review. No further edits should be made to this section. 

The result of the move request was: page moved JohnBlackburne wordsdeeds 10:13, 15 February 2014 (UTC)

Rotation group → Rotation group (disambiguation) – From the recent discussions it seems clear many of the topics here are related, and that 'rotation group' is more than just a title but is the (concrete) thing that relates them. I thought of creating an article but one already exists, orthogonal group. So rotation group should redirect there, this page should be at rotation group (disambiguation) with rotation group as its primary topic. Relisted. BDD (talk) 00:00, 7 February 2014 (UTC) JohnBlackburne wordsdeeds 20:14, 22 January 2014 (UTC)
 * There a two reasonable option:
 * The new “rotation group” should redirect to rotation (mathematics) with a dab hatnote – I see no point in separate descriptions of the same subject.
 * Leave the stuff at rest.
 * In any case, the rotation (mathematics) article shall be cleansed from enumerative scum and made more conceptual. Incnis Mrsi (talk) 15:40, 23 January 2014 (UTC)


 * Support per nom. bd2412  T 13:27, 27 January 2014 (UTC)
 * Support per nom. Logical suggestion to address a messy situation. Xoloz (talk) 02:57, 15 February 2014 (UTC)
 * The above discussion is preserved as an archive of a requested move. Please do not modify it. Subsequent comments should be made in a new section on this talk page or in a move review. No further edits should be made to this section.

I closed the above procedurally as the page has already been moved – I would not normally close a discussion I started otherwise.-- JohnBlackburne wordsdeeds 10:15, 15 February 2014 (UTC)

cleanup according to WP:MOSDAB
This dab needs a cleanup. We have the same entry listed twice and I see no reason why. There may be better options like a WP:BROADCONCEPT? Widefox ; talk 02:14, 20 February 2014 (UTC)
 * I agree with . IMO, this page should be a redirect to rotation group. For the moment, rotation group is a redirect to orthogonal group. Until recently, "orthogonal group" and "rotation group" were wrongly considered as synonymous in WP. The true thing is that, the rotation group is a subgroup of the orthogonal group (the subgroup of the transformations that preserve the orientation). IMO, there are two acceptable ways to solve the issue: either edit Orthogonal group for well covering both topics (this has been partially done), and remove this disambiguation page, or move this disambiguation page to Rotation group and clean it as a true article (it is not even a SIA). See Wikipedia talk:WikiProject Mathematics‎‎ for a related discussion. D.Lazard (talk) 13:14, 20 February 2014 (UTC)


 * See the requested move immediately above: it was moved here after that, which was open for three weeks, with no objections (the only editor who doesn't clearly support Incnis Mrsi actually did the move – their objection was over where the subsequent redirect should go). We need a disambiguation page somewhere; currently as rotation group is the primary topic we need it for readers who use that redirect to get to orthogonal group but don't actually want that article. The other option would be to move it back, but that would require another RM, and it seems too soon, unlikely that the consensus has changed so soon.-- JohnBlackburne wordsdeeds 13:48, 20 February 2014 (UTC)
 * A second BROADCONCEPT? There is one already. join the discussion about a real problem. After the principal question of the special orthogonal group will be resolved, it will become easier to fix secondary stuff such as dab pages. Incnis Mrsi (talk) 14:02, 20 February 2014 (UTC)
 * Thanks for the info and invite, and yes sounds like it's in hand by the maths project already. As you say the dab project perspective is secondary, although the cleanup tag may be kept in the meantime.
 * Separately, can anyone from the maths project explain why there's a mathdab template, but no dab class in the maths rating template? I left the class blank (as it's not a list). I posted the question at Template talk:Maths rating. Widefox ; talk 16:04, 20 February 2014 (UTC)
 * The template is not meant for DAB pages. They are not articles, so don't get rated like articles, or have importance like articles. The mathdab template is an odd thing: I don't think it's needed either as the point of DAB pages is to link articles by title, not topic: if they're all mathematical articles its because that's how the word(s) linking them are used in the English language, it's not a mathematical connection. But it does no harm and put the DAB page in the main category for such pages.-- JohnBlackburne wordsdeeds 07:02, 21 February 2014 (UTC)
 * Sure, the question is why not. Other projects have a dab class. IMHO useful to maintain mathdabs (at least). If it's important enough to have a non-default dab template, I would assume that project would be interested in maintaining them. Projects sometimes use them on mixed dabs let alone project exclusive dabs. I personally don't see the need for all these dab templates so would replace them with the categories - another benefit being that the cleanup template can be used. Widefox ; talk 17:53, 21 February 2014 (UTC)

"also"
I am puzzled by Widefox's addition of "also", in "Rotation group may also refer to:". The links below this line are not additional uses of "rotation group" as defined in the preceding line, they are special cases of it. Maybe the page could start

A rotation group is any group of orientation-preserving orthogonal transformations of a Euclidean vector space, which have a common fixed point.

Rotation group may more specifically refer to:

[italics used here to show my proposed changes] Maproom (talk) 08:55, 9 March 2014 (UTC)


 * See MOS:DABPRIMARY – 'may also refer to' is the standard way of phrasing it. The page is just meant to list articles, not try to establish how the topics are related, which "more specifically" does.-- JohnBlackburne wordsdeeds 09:50, 9 March 2014 (UTC)


 * Maproom, as JohnBlackburne said, see WP:MOSDAB, specifically MOS:DABPRIMARY (I think I may have created that shortcut). If they are all examples of the primary topic, then see my comment (and more importantly Incnis Mrsi's) above about a BROADCONCEPT.
 * The dab still needs cleanup, but as the mathsdab template doesn't have a cleanup attribute like the main disambiguation template I'd added the latter. JohnBlackburne just because we're waiting for the maths project editors to sort the situation doesn't mean we should remove the cleanup template. I'll put the standard cleanup one on in the meantime, as I believe there's consensus that cleanup is required. Widefox ; talk 10:03, 9 March 2014 (UTC)


 * What cleanup is needed? There are no red links, no links to inappropriate pages like other DAB pages (except where they should be), project pages, entries are not too long or containing multiple blue links.


 * If you mean your assertion this needs to be a broad concept, that's not cleanup but a change of purpose of the page. And we that we had a discussion on the page only a month ago, with outcome that the page remained a disambiguation page but was moved – that was the consensus. We definitely need a disambiguation page, and this is the most logical location for it. As this is nothing about cleanup I'll remove the template-- JohnBlackburne wordsdeeds 10:19, 9 March 2014 (UTC).


 * When I added the template I detailed what (see above "cleanup according to WP:MOSDAB"). That remains unresolved. It appears to have consensus. I mean at the very least, a basic thing not fixed but discussed above which I believe is acknowledged, so would be good to either fix it or leave the cleanup template John. Let me reiterate...
 * the same article is listed twice Orthogonal group (redirects from rotation group and special orthogonal group)
 * my understanding (solely from above) is that this dab is waiting for the primary task being done by the maths project on the broadconcept (I haven't checked that as I'm not sure how much I could contribute)
 * I will seek further opinions at the dab project. Widefox ; talk 10:53, 9 March 2014 (UTC)
 * Everything on this list is a type of the primary topic. This should just be a list article (or set index list article), or concept article, not a disambiguation page. -- JHunterJ (talk) 11:24, 9 March 2014 (UTC)

The multiple links is the first thing discussed on this page: see. After the discussion I accepted Incnis Mrsi's arguments and left them in. The further discussions below that led to the page move discussion and the determination that this page should be moved to its current location. I see various discussions since but none that challenges that outcome. Normally there are two ways to challenge a RM that comes to a clear conclusion (as opposed to "no consensus"). A Move review can be used in exceptional cases to challenge a RM discussion that has been inappropriately ended. Or a further RM discussion, though it's normal to do that only after some time has passed, to allow time for consensus and/or circumstances to change.-- JohnBlackburne wordsdeeds 11:36, 9 March 2014 (UTC)


 * As further opinion is saying the obvious - this is not a dab, JohnBlackburne, may I ask you to restore the maths project template on this article too . Regards  Widefox ; talk 19:08, 9 March 2014 (UTC)