Talk:Point group
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[edit] Override of redirect
Point group had been redirected to crystallographic point group, suggesting either that these were synonyms, or that the crystallographic version was so much more important that the more general concept did not warrant discussion. In fact, that article does not even acknowledge the distinction.
Yet the more general point group is essential for purposes outside crystallography. Chemistry, in particular, describes the symmetries of molecules and bonds, where the crytallographic restriction is an unwanted intrusion. Mathematics also needs the full generality to talk about finite symmetry groups with a fixed point, and it is unacceptable to omit the icosahedral group, say, because of the crystallographic restriction.
Perhaps some of the pages that link to point group ought to be edited to link to the more appropriate page. Of course, crystallographic point group could be made a subset of this article if it has little additional data to offer. But the status quo ante was an inappropriate absorption.
KSmrq 2005 July 4 23:52 (UTC)
[edit] Merge?
I've suggested that the article on point groups in three dimensions be merge into this one. See the talk page of that article for discussion. O. Prytz 00:02, 6 June 2006 (UTC)
- Sorry; just saw this suggestion. Even though I originally wrote this article, I took it off my watchlist after Patrick persistently mangled its accuracy and chopped it to pieces. You may find that an early version would be more satisfactory. I certainly would. For example, the current article says "The 3D discrete point groups are heavily used in chemistry", introducing a mistake not found in the original, which says "The 3D point groups are heavily used in chemistry". What's the difference? The symmetry of the hydrogen atom, for one! (Or of any linear molecule, such as acetylene.) I tired of arguing with Patrick over numerous pages, and could no longer bear to look at the butchery here. (If you scan through the archives of his talk page, you'll find he's still a persistent source of trouble.) The meek may inherit the Earth, but the bullheaded seem to win on Wikipedia. --KSmrqT 17:02, 27 June 2006 (UTC)
- Ignoring the above (what else can I do?) I would suggest that the whole area of symmetry space group point group crystal system etc. etc. needs re-engineering from the ground up. Its a problem with the Wiki approach that one perspective on a broad topic is not the same as another, but I feel we need one overall perspective into which to fit the individual articles, allowing a convenient fit with the fields of mathematics, chemistry and protein crystallography. In conclusion, don't merge; redesign. Lets start a list of articles that need to at least coordinate their content. Perhaps a hierarchical TOC for the whole 'topic', then we can decide what information goes into what articles... Its a big job. --Dan|(talk) 07:51, 30 June 2006 (UTC)
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- Right. Sorry for the rant; I prefer to look for solutions and ways forward, not just vent frustrations.
- Reorganization and some rewriting could be helpful. The good thing is, we have a fair amount of content to work with. The bad thing is … the same!
- There are interesting challenges in how to factor, because mathematics, physics, chemistry, and other disciplines are entangled. I got sucked in through the article on wallpaper groups, as a little recreational diversion. Then it turned out we needed an article on the crystallographic restriction theorem, so I wrote that. Along the way I found that point group was being redirected to crystallographic point group (Patrick's myopic perspective), so I killed the redirect and created new content. I've had a recreational interest in minerals and crystals (and a friend with a rock shop), so I've got some awareness of that area; I also looked into crystallography as used for biochemistry, physics, and so on; and I'd been reading on the use of group theory and symmetry in physical chemistry. At the heart of it all is the mathematics — for me, anyway. But we have to (and I want to) write for all these interests.
- I'll do what I can to support a redesign, but I do have some other Wikipedia things I'm working on, as well as a life. ;-)
- If you want to take the lead in organizing a list of articles, great. I think that would be a good thing even if nothing else is done. I wonder if somewhere there is a tool that can reveal the link structure of articles; but we can always crawl through and assemble a map of connections by hand if we must.
- Actually, it would be good to check with existing projects for mathematics, physics, chemistry, or whatever and see if something already exists that we don't know about. And if not, figure out where to collect the results. Drop me a note on my talk page when you're ready for help. --KSmrqT 15:49, 30 June 2006 (UTC)
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- A reworking of the articles relating to crystallography is sorley needed. I've been tinkering a little here and there, but I feel sorry for anyone new to crystallography reading these articles. A prototype for a hierarchy for the crystallography articles might look something like this:
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- If we think along these lines, the crystal structure article should briefly introduce the four sub-topics, and tie all of them together. The articles for each sub-topic should, of course, be more in-depth. The articles we have today aren't completely useless, but they're confusing and inconsistent, and I'd be happy to help in reworking them. My problem is that I have very little interest in the mathematics of e.g. group theory, so any contributions I make would be more on the practical use of these concepts in crystallography. Furthermore, I feel pretty strongly that any mathematics should be kept to a minimum. Others don't agree. The way I see it, many articles might have to consist of two quite separate parts (description of practical use, and the mathematical basis), or perhaps split into two articles. In a way I'm quite content that we have two articles on point groups: crystallographic point group and point group (although the third on point groups in three dimensions is probably redundant). Should we start by working on the hierarchy above and try to agree on a set of articles that we want to work on? O. Prytz 19:59, 3 July 2006 (UTC)
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- I sympathize with a practical interest, but it is not practical to write for an encyclopedia without addressing a broad range of interests. Even were we to focus on crystallography alone, a great deal of mathematics would be natural, even necessary.
- Sometimes the solution is to split articles. However, the style manual for mathematics recommends that a mathematical article should do its best to begin with material suitable for a wider audience, then build in abstraction and generality as it goes. For many articles that may suffice. This demands good writers who are sensitive to novices, practitioners, and higher mathematicians, but it can be done.
- Be sure to look at the category, and at the crystallography article itself. Some time back I added a number of external links to the article. This one should be of particular interest to mineralogists, while this one (found through the IUCr link) would be of more interest to biochemists. I did not spend time on the contents of the article, which remains weak. If I might suggest a miniproject, go to work on that. --KSmrqT 00:52, 4 July 2006 (UTC)
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[edit] "discrete"
This is mentioned twice near the beginning of the article as a modifier to "point group", but is never defined. I think this should be done so, or removed. Sounds like from the previous discussion it is important; I take it excludes groups like C∞, yes? Baccyak4H 19:15, 2 November 2006 (UTC)
