Talk:Distance geometry

Molecules structure

It seems that the term is only used for molecules structure?? Tosha 18:14, 3 October 2005 (UTC)

Applications

Probably, the most "real-life application" is GPS? — Mikhail Ryazanov (talk) 08:18, 24 January 2011 (UTC)

Destruction of material by Toninowiki

A series of edits were done on this article on November 11 by user:Toninowiki, who destroyed all references to higher dimensions, which are crucial to the point of the article. Now someone in another forum is telling me that my link to this article is not much appreciated because it doesn't go into higher dimensions. I've restored the material that was destroyed. Michael Hardy (talk) 21:22, 25 January 2014 (UTC)

GA Review

This review is transcluded from Talk:Distance geometry/GA1. The edit link for this section can be used to add comments to the review.

Reviewer: Adamant.pwn (talk · contribs) 23:22, 29 July 2019 (UTC)

Rate	Attribute	Review Comment
1. Well-written:
	1a. the prose is clear, concise, and understandable to an appropriately broad audience; spelling and grammar are correct.	Check
	1b. it complies with the Manual of Style guidelines for lead sections, layout, words to watch, fiction, and list incorporation.	Check
2. Verifiable with no original research:
	2a. it contains a list of all references (sources of information), presented in accordance with the layout style guideline.	Check
	2b. reliable sources are cited inline. All content that could reasonably be challenged, except for plot summaries and that which summarizes cited content elsewhere in the article, must be cited no later than the end of the paragraph (or line if the content is not in prose).	Introduction and definitions section has no inline citations. Please, provide some, so it may be verified that concepts really belong to the topic and are introduced correctly. As for dimension (dimensionality?) reduction I don't even really see how it correlates with distance geometry. Some explanation here would be helpful. And what's the context of hyperbolic navigation? It would be helpful to provide some reasoning on why do we know differences, but not exact time for each station.
	2c. it contains no original research.	Check
	2d. it contains no copyright violations or plagiarism.	The very first sentence in the article appears here. If it was taken from there, it may go as wp:copyvio. Any comments on this?
3. Broad in its coverage:
	3a. it addresses the main aspects of the topic.
	3b. it stays focused on the topic without going into unnecessary detail (see summary style).
	4. Neutral: it represents viewpoints fairly and without editorial bias, giving due weight to each.	Check
	5. Stable: it does not change significantly from day to day because of an ongoing edit war or content dispute.	Check
6. Illustrated, if possible, by media such as images, video, or audio:
	6a. media are tagged with their copyright statuses, and valid non-free use rationales are provided for non-free content.	Check
	6b. media are relevant to the topic, and have suitable captions.	Check
	7. Overall assessment.	In introduction and definitions $c$ is used presumably for the speed of light. That should be clarified explicitly. Please familiarize yourself with writing style in mathematics for wikipedia articles. In particular, referring to "we" should be avoided. "For all $x,y\in R$: positivity" – I suppose some verb is needed here, like "for all ... holds: ..." or something. "an isometric embedding into is defined by" – embedding from what into what? $\mathbb {R} ^{k}$ is clearly a metric space, so it may not be possible to provide such an embedding in $\mathbb {R} ^{k}$. Any comments here? "affinely independent, iff they cannot ..." – using iff clause is not recommended for definitions. Simple if is ok here. Also I'd suggest not to write "A iff B iff C" and keep it simpler. "then they make up the vertices of an" – I suppose it should be "a" here? "Cayley–Menger determinants, named after Arthur Cayley and Karl Menger, are determinants of matrices of distances between sets of points." – why do the last column and row consist of ones then? In Cayley-Menger determinant it is said that points $A_{0},\dots ,A_{n}$ are in Euclidean space. And article say it's for semimentric space. Where's the truth? Is Cayley-Menger determinant connected in any way with Gramian matrix? With Euclidean distance matrix? "Any $(n+3)$-point subset $S'$, obtained by adding any two additional points of $R$ to $S$, is congruent to an $(n+3)$-point subset of $\mathbb {R} ^{n}$." – what is meant here by congruent? "A proof of this theorem in a slightly weakened form (...) is in [13]." – This information really has little encyclopedic significance. Simple inline citation would suffice. More importantly, theorem shouldn't just hang in the air. Please, provide some summarized info about its significance and usages. "The following results are proved in Blumethal's book[12]." – Some introduction instead of this would be useful as well as for previous point. Also the whole section probably should be largely reformatted. First question I come up with looking on the section is "why is it here?" and the second one is "what's going on here?". "A necessary condition is easy to see" – no, it's not. The whole section looks like a heap of facts somehow connected together. Starting here it's extremely hard to follow the lead and something should be done about this. "Thus, Cayley–Menger determinants give a concrete way to calculate whether a semimetric space can be embedded" – and what about ways to find such embedding? In general, all issues seem easily fixable, except for "Characterization via ... determinants" section. This one seems to need a lot of improvement. Please, update here whenever you fix something or reply to comments. I'll look into it again later. --Adamant.pwn (talk) 01:51, 31 July 2019 (UTC)

Thanks for your very detailed review. I just want to say that the first sentence was an astonishing coincidence, and there is no copyright violation. Now I'll have a cool story to tell.

Since I have no time to update the page, I would have to leave it at that for now. Maybe later I'll update it as suggested. pony in a strange land (talk) 08:15, 4 August 2019 (UTC)

• It actually seems that sentence in wikipedia article was there (since 2014) before the work (published in 2015), so maybe they just copied it. ${\texttt {adamant}}$^{(talk/contribs)} 03:52, 5 August 2019 (UTC)

@Adamant.pwn and Cosmia Nebula: Hey folks. Just wanted to check in on how this review is progressing since there hasn't seem to been any progress in the past month. :) --Dom497 (talk) 02:34, 20 September 2019 (UTC)

• Hi. There was no update from pony in a strange land yet. Should I drop the nomination in this case? ${\texttt {adamant}}$^{(talk/contribs)} —Preceding undated comment added 12:36, 22 September 2019 (UTC)

• @Adamant.pwn: I would make one last effort to notify them. If they don't respond within a reasonable amount of time then you can just fail the nomination.--Dom497 (talk) 16:39, 22 September 2019 (UTC)

• Adamant.pwn, I have just posted to the nominator's talk page that they need to take action, otherwise the nomination will likely close in a matter of days. May I suggest that if nothing is done, the nomination be closed by the end of September, or if you want to be exceptionally lenient, no later than October 4, two months after they posted Maybe later I'll update it as suggested in their sole edit to this page. Under the circumstances and the more than generous delay, I certainly wouldn't leave it open any longer than that. BlueMoonset (talk) 01:51, 26 September 2019 (UTC)

• Yep, fine with me. ${\texttt {adamant}}$^{(talk/contribs)} 01:55, 26 September 2019 (UTC)

@Adamant.pwn: Still no response from the nominato and the date is October 4, so maybe time to fail this article. HawkAussie (talk) 00:25, 4 October 2019 (UTC)

• It seems so. Nomination is failed. ${\texttt {adamant}}$^{(talk/contribs)} 10:13, 4 October 2019 (UTC)

This article could use a good deal of improvement

There are numerous symbols used in the article that are nowhere defined.

This is a terrible idea for an encyclopedia article.

I hope someone can define in the article the symbols t_A, t_B, t_C, and d_ij, among others. 2601:200:C000:1A0:D814:9114:E269:A7A7 (talk) 18:51, 28 April 2022 (UTC)

They're defined: The times it takes for a radio signal to travel from the stations to the receiver, $t_{A},t_{B},t_{C}$ and d is defined in the sentence beginning Explicitly, we define a semimetric space MrOllie (talk) 18:55, 28 April 2022 (UTC)

Content error

Under “Characterization via Cayley–Menger determinants” it is noted that the following results are proved in Blumenthal's book [12].

Unfortunately, that's wrong. The results presented by Wikipedia only roughly reflect Blumenthal's work and contain errors.

This can easily be checked by means of a simple counterexample: According to Blumenthal, the semimetric space with the distance matrix

0 3 4 8

3 0 1 4

4 1 0 2

8 4 2 0

cannot be embedded in any space Rⁿ, but according to the Wikipedia article it can, namely for n=3.

The Cayley-Menger determinants given by the principal submatrices with elements of the 4, the first 3 and the first 2 lines satisfy the embedding conditions of Wikipedia. However, the remaining three triangles of the potential tetrahedron do not fulfill the triangle inequality.

These misrepresentations of the central theorem of distance geometry are not peanuts.

~~~~

K2357W (talk) 09:24, 2 July 2022 (UTC)