Talk:Rank of a group
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Crystallographic examples
[edit]I removed the the 2- and 3-dimensional crystallographic groups and this was reverted by the editor who added them (pinging Ryanfrom). I strongly believe they do not belong in this article, and here is a longer justification of my edit summary. These examples are not particularly interesting by themselves from the point of view of these articles, as the rank computation boils down to looking at an explicit list and dealing with each case is just a triviality or a tedious exercise. They do not illustrate any general principle for computation of rank either. Thus they only clutter the examples section. (On the other hand it would make sense to have the rank values given in the articles for these groups if this is not already the case.) Without a substantial answer to these points i will remove these examples again.
As an addendum, i note that the papers quoted to support the addition are not published in a math journal but in crystallographic journal, if the rank of crystallographic groups has a real significance for actual crystallography this would certainly warrant a mention here, but likely not in the "examples" section. jraimbau (talk) 08:03, 31 August 2024 (UTC)
- Dear colleague, I understand the logics of the above judgement, however, the explanatory statements like "these examples are not particularly interesting by themselves" is just a matter of taste. Under the subtitle "Known facts and examples" there is the right place for known facts and examples, that is it. I strongly beleive deleting a contribution done in good faith because of the reasons mentioned above contadicts basic principles of Wikipedia, especially when applied to a wiki-newcomer. Not destructuve editing is more appropriate option than deleting, anyway. So, if anyone wishes to clarify the text, to add some details, etc., he is welcome. Ryanfrom (talk) 09:29, 11 September 2024 (UTC)
- Not all examples are equal, and the "examples" section should not be cluttered by too many of them for it not to become useless. In the state previous to your edit there were quite a few already, which were largely sufficient to illustrate the concept, and some which are of interest by themselves. So for adding a new example it seems reasonable to ask that either the rank computation in this example should be interesting by itself (because it uses new tools, or it makes a general principle apparent), or the value of the rank itself should be significant (for example the fact that all non-abelian simple groups are of rank 2 is interesting, or the fact that there exists lattices of bounded rank in hyperbolic 3-space in contrast with hyperbolic 2-space, or the rank-vs-Heegaard genus for 3--manifolds). I don't see any of these features in your additions. Unless you can give a good reason why these examples should remain here they should not, otherwise anyone can add their favorite group and the list would be endless. jraimbau (talk) 17:05, 11 September 2024 (UTC)
- Yes, anyone can add "favorite group" he deals with, however, not anyone can make the contribution properly (conforming all that is already written in the text of the article, with proper links etc.), so the list of examples will hardly become "endless".
- The examples under discussion cover three important families of groups, each with a detailed article in Wikipedia indicating their importance. The majority of chemists and crystallographers is less profound in pure group theory than a pure mathematician specialized in this field, and some properties of groups are less familiar to such scientists. But what, in general, is a point group, a plane group, a rod group, a layer groupm is known to everyone from them. Thus, the generalized results on ranks of these groups may be of interest to these people as such, with no extra speculations.
- Another point is that Wikipedia:Ownership of content states that none does not own the article, nor has any right to dictate what the article may or may not say. I am grateful for your recommendations and will probably follow them in future. Right now I can offer to reduce the 3 positions of the list with the new examples into the only one in order to make the list less "endless". You are also encouraged to make improvements you like in accordance with Wikipedia:Editing policy, viz. instead of removing content from an article or reverting a new contribution, consider:
- Rephrasing or copy-editing to improve grammar or more accurately represent the sources
- Formatting or sourcing on the spot
- Tagging it as necessary
- Correcting inaccuracies, while keeping the rest of the content intact
- Merging or moving the content to a more relevant existing article, or splitting the content to an entirely new article
- Adding another point of view to the existing points of view to make the article more balanced
- Requesting a citation by adding the {{citation needed}} tag, or adding any other appropriate cleanup tags to content you cannot fix yourself
- Doing a quick search for sources and adding a citation yourself
- Repairing a dead link if a new URL for the page or an archive of the old one can be located
- Merging the entire article into another article with the original article turned into a redirect as described at performing a merge
- Fixing errors in wikitext or formatting
- Have a good evening! Ryanfrom (talk) 19:26, 11 September 2024 (UTC)
- Dear colleague, I have made some improvements. Please, look. Ryanfrom (talk) 19:40, 11 September 2024 (UTC)
- Not all examples are equal, and the "examples" section should not be cluttered by too many of them for it not to become useless. In the state previous to your edit there were quite a few already, which were largely sufficient to illustrate the concept, and some which are of interest by themselves. So for adding a new example it seems reasonable to ask that either the rank computation in this example should be interesting by itself (because it uses new tools, or it makes a general principle apparent), or the value of the rank itself should be significant (for example the fact that all non-abelian simple groups are of rank 2 is interesting, or the fact that there exists lattices of bounded rank in hyperbolic 3-space in contrast with hyperbolic 2-space, or the rank-vs-Heegaard genus for 3--manifolds). I don't see any of these features in your additions. Unless you can give a good reason why these examples should remain here they should not, otherwise anyone can add their favorite group and the list would be endless. jraimbau (talk) 17:05, 11 September 2024 (UTC)