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Handshaking lemma article. This is
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I read: "every finite undirected graph has an even number of vertices with odd degree"
Why is the graph supposed undirected?
It seems to me this this lemma is also valid for directed graphs...
For directed graphs there may exist odd numbers of vertices with odd indegree or odd outdegree (consider the graph with one directed edge). It's true for total degree but that's essentially the same as the degree in the underlying undirected graph. —
David Eppstein (
talk) 15:52, 28 September 2013 (UTC)reply
In the very first sentence, on my first reading, I understood it to say that "every finite undirected graph has an even number of vertices" (clearly untrue), and only after a minute's reflection saw that it meant to say that, of the vertices of any finite undirected graph, the number of vertices that have an odd number of edges touching them must be even. The second sentence tends toward the same misunderstanding, in my opinion. Is there a way to accurately state the main idea that eliminates this potential confusion, while staying smooth and easy to read? Otherwise, the prose is clear and professional. The article also appears to comply with the relevant sections of MoS.
Reworded to avoid this ambiguity. —
David Eppstein (
talk) 23:30, 12 November 2021 (UTC)reply
Also, I think the section that mentions directed graphs would benefit from the point you made in the talk page ("It's true for total degree but that's essentially the same as the degree in the underlying undirected graph.").
Ok, but that would require a reliable source that makes the same point. Do you know of one? —
David Eppstein (
talk) 23:30, 12 November 2021 (UTC)reply
I don't; if you feel that the idea that the sum of a node's indegree and outdegree in a directed graph is equal to the degree of the corresponding node in the underlying undirected graph is non-obvious enough to merit citation, then I guess it can be left out. Probably a good clarification to have if this were to e.g. run for FA. -
Bryan Rutherford (
talk) 21:04, 13 November 2021 (UTC)reply
There is a reference section containing numerous citations to reputable published sources. I don't see any sign of plagiarism from online sources. All of the online sources substantiate the claims they're cited for, and almost all of the cited sources are online. The content looks verifiable.
The article stays appropriately focused on its topic. I think the statement, proof, and some major applications constitute broad coverage of the topic, though there are probably many other applications that could be explored (I'd love to see something about its
relevance to chemistry, but that can wait!).
The presentation of the topic is suitably neutral, not e.g. exaggerating the importance of the topic or unduly promoting any of the people involved in its development.
It is stable.
No edit wars, etc.:
No sign of edit wars, and no edits since being nominated for GA.
It is illustrated by images and other media, where possible and appropriate.
The illustrations have suitable licenses and are visually clear, with strong captions explaining their relevance.
Overall:
Pass/Fail:
A clear, focused article on a well-defined topic! I'll work through the sourcing as soon as I can, and if no issues come up there, then I think I'll just have the prose niggles. -
Bryan Rutherford (
talk) 22:25, 12 November 2021 (UTC)reply
The only issue I raised has been addressed, and everything else looks great. This article is hereby approved for GA. Well done! -
Bryan Rutherford (
talk) 21:04, 13 November 2021 (UTC)reply
Did you know nomination
The following is an archived discussion of the DYK nomination of the article below. Please do not modify this page. Subsequent comments should be made on the appropriate discussion page (such as
this nomination's talk page,
the article's talk page or
Wikipedia talk:Did you know), unless there is consensus to re-open the discussion at this page. No further edits should be made to this page.
Improved to Good Article status by
David Eppstein (
talk). Self-nominated at 19:51, 15 November 2021 (UTC).reply
Promoted to GA recently on November 13, media usage looks fine, plagiarism free (Earwig says 3.8%), hook is properly sourced, and article seems thoroughly researched. This should be good to go. ɴᴋᴏɴ21❯❯❯talk 23:32, 15 November 2021 (UTC)reply
The article is looking great! However, I'm looking to inquire about the consistency of "vertices, nodes, etc" Is there a Wikipedian standard for terms used in Graph Theory such that they don't get used so inconsistently? I am very used to "pick a style and apply it ad infinitum." Obviously the matter is trivial, but I do wish to know.