Talk:Kawasaki's theorem

Kawasaki's theorem has been listed as one of the Mathematics good articles under the good article criteria. If you can improve it further, please do so. If it no longer meets these criteria, you can reassess it.
Review: September 13, 2017. (Reviewed version).

A fact from Kawasaki's theorem appeared on Wikipedia's Main Page in the Did you know column on 22 April 2011 (check views). The text of the entry was as follows:

Did you know... that according to Kawasaki's theorem, an origami crease pattern with one vertex may be folded flat (pictured) if and only if the sum of every other angle between consecutive creases is 180º?

A record of the entry may be seen at Wikipedia:Recent additions/2011/April.

Wikipedia

DYK[edit]

There were 10.3 thousand = 4.7 + 5.6 thousand viewers for this DYK, in the two days in which this article appeared (in different time zones). Kiefer.Wolfowitz 23:21, 26 April 2011 (UTC)[reply]

Thanks, but where did you get these numbers? When I try it [1] I get 4.7k + 5.6k. Still, well over the threshold of 5k for listing in WP:DYKSTATS. —David Eppstein (talk) 23:39, 26 April 2011 (UTC)[reply]

I added this DYK to WP:DYKSTATS. (I corrected my error. My long-term memory is better ....) Kiefer.Wolfowitz 17:58, 27 April 2011 (UTC)[reply]

Unfortunately this is not eligible for WP:DYKSTATS. It was on the Main page on April 22, from 18:00 to midnight (UTC). It wasn't on the Main page on April 23, so the additional 5.6k hits don't count (see rule 1). Sorry. —Bruce1ee^talk 05:20, 28 April 2011 (UTC)[reply]

Bruce, I don't understand your comment. Rule 1 states that both days count, if the article appeared over two days (because of different time zones): The "two-day period after the article's DYK appearance if the article was featured on the next day as well".

I couldn't check the queuing information, now, to specify the exact incidence of its main-page appearance. Thanks, Kiefer.Wolfowitz 09:17, 29 April 2011 (UTC)[reply]

The article appeared on the Main page here on April 22 at 18:00 (UTC) until here on April 23 at 00:00 (UTC). It might have also featured on April 23 in other time zones, but the times used here are UTC. Rule 1 says the page views from the next day can be added "if the article was featured on the next day as well", which it wasn't – it was only on the Main page on April 22. I hope I've explained this properly. —Bruce1ee^talk 09:57, 29 April 2011 (UTC)[reply]

Hi David & Kiefer, there has been an update of the DYKSTATS rules that point out that hooks exiting the Main page around 00:00 UTC get extra DYK views the next day (see DYKSTATS rule 1). What this means is that I got it wrong, and that the next day's views for Kawasaki's theorem should have been counted as stated above. I've added the 10.3k views to DYKSTATS/Archive 2011#April 2011. I'm sorry I messed you guys around, but I wasn't aware of this at the time. —Bruce1ee^talk 15:07, 26 May 2011 (UTC)[reply]

proof against global flat-foldability[edit]

"Tom Hull (1994) conjectured that global flat-foldability could be tested by checking Kawasaki's theorem at each vertex of a crease pattern, and then also testing bipartiteness of an undirected graph associated with the crease pattern, but this conjecture was disproven by Bern & Hayes (1996), who showed that the problem of testing global flat-foldability is NP-complete."

The conjecture is not disproven through the fact that the problem is NP-complete. As the P=NP-Problem is not yet solved, it might be that all NP-problems are solvable in polynomial time. --Mathmensch (talk) 15:40, 25 May 2013 (UTC)[reply]

The conjecture was disproved, *and* they showed that it was NP-complete. In any case NP-completeness makes simple polynomial-time characterizations such as the conjectured one highly unlikely.—David Eppstein (talk) 15:46, 25 May 2013 (UTC)[reply]

That bit was about checking the flat-foldability of any particular crease pattern, he conjectured passing those two simple tests would ensure it but that's not true, it is a lot more complicated. You can make a crease pattern the flat foldability of which is equivalent to solving a particular logic problem that is NP-complete. Dmcq (talk) 16:21, 25 May 2013 (UTC)[reply]

Total confusion[edit]

Nothing can be undesrtood from this page. All the material was mixed up so badly that one is not sure if this is the asked page. What is the Kawasaki theorem? Where exactly is the body of it? Is it about angles or folding valleys and mountains, or maybe about all. Put this together and let away the history. — Preceding unsigned comment added by 79.113.124.72 (talk) 19:35, 3 November 2016 (UTC)[reply]

Your English is (perhaps ironically) ungrammatical and difficult to understand. In any case, the theorem is the one found in the section "Statement of the theorem", in the sentence that begins "Then Kawasaki's theorem is the statement that...". —David Eppstein (talk) 20:13, 3 November 2016 (UTC)[reply]

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GA Review[edit]

This review is transcluded from Talk:Kawasaki's theorem/GA1. The edit link for this section can be used to add comments to the review.

Reviewer: Hawkeye7 (talk · contribs) 05:29, 13 September 2017 (UTC)[reply]

GA review – see WP:WIAGA for criteria

Is it well written?
A. The prose is clear and concise, and the spelling and grammar are correct:

B. It complies with the manual of style guidelines for lead sections, layout, words to watch, fiction, and list incorporation:
Is it verifiable with no original research?
A. It contains a list of all references (sources of information), presented in accordance with the layout style guideline:

B. All in-line citations are from reliable sources, including those for direct quotations, statistics, published opinion, counter-intuitive or controversial statements that are challenged or likely to be challenged, and contentious material relating to living persons—science-based articles should follow the scientific citation guidelines:

C. It contains no original research:

D. It contains no copyright violations nor plagiarism:
Is it broad in its coverage?
A. It addresses the main aspects of the topic:

B. It stays focused on the topic without going into unnecessary detail (see summary style):
Is it neutral?
It represents viewpoints fairly and without editorial bias, giving due weight to each:
Is it stable?
It does not change significantly from day to day because of an ongoing edit war or content dispute:
Is it illustrated, if possible, by images?
A. Images are tagged with their copyright status, and valid fair use rationales are provided for non-free content:

B. Images are relevant to the topic, and have suitable captions:
Nice image.
Overall:
Pass or Fail:

I see no problems with this article. I believe it meets the GA criteria in all respects. Hawkeye7 (discuss) 05:30, 13 September 2017 (UTC)[reply]