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Contradiction in proof section?
The last paragraph in Four color theorem#Proof by computer: 'They responded that the rumors were due to a "misinterpretation of [Schmidt's] results" and obliged with a detailed article' - without further comment it looks like Schmidt was wrong. But then we learn that their book later " explained and corrected the error discovered by Schmidt [...]", so Schmidt was right? Related question: Why was it "a rumor" years after the master thesis was published? --mfb (talk) 07:22, 16 May 2019 (UTC)[reply]
Requested move 22 August 2020
The following is a closed discussion of a requested move. Please do not modify it. Subsequent comments should be made in a new section on the talk page. Editors desiring to contest the closing decision should consider a move review after discussing it on the closer's talk page. No further edits should be made to this discussion.
Oppose on grounds given. Most of the scholarly, reliable sources don't punctuate this. See the references section, with titles like "The Four Color Theorem: History, Topological Foundations and Idea of Proof." There do appear to be a few sources that punctuate this, but we should follow the preponderance of the sources here. SnowFire (talk) 16:25, 22 August 2020 (UTC)[reply]
That would involve switching from American English to English English. As Appel is American and Haken taught in America I think color is the most appropriate spelling to use.--Salix alba (talk): 16:57, 22 August 2020 (UTC)[reply]
Oppose because this article tells about a theorm about four colors, which IMO the correct title should be Four colour theorm for more NPOV title. 182.1.13.112 (talk) 16:59, 22 August 2020 (UTC)[reply]
Oppose hypernated is not needed for that article and thw title should be remained as this, thought IMO, the correct title of Four color theorem shouldn't be color but Colour. 36.77.93.106 (talk) 23:54, 22 August 2020 (UTC)[reply]
Stop replying to this discussion repeatedly with many IPs. It's annoying and doesn't strengthen your position at all. --mfb (talk) 01:06, 26 August 2020 (UTC)[reply]
OP here. While I personally disagree on keeping the title without hyphenation, I respect the counterarguments and the current democratic consensus. This reminds me of the debate regarding air superiority fighter vs air-superiority fighter. It seems to be a matter of stylistic preference. Thanks for your input. Electricmaster (talk) 10:34, 26 August 2020 (UTC)[reply]
The discussion above is closed. Please do not modify it. Subsequent comments should be made on the appropriate discussion page. No further edits should be made to this discussion.
Simple Proof
On a square grid start with a single square. Add a layer of squares around it so that it becomes a 3x3 square. Each square you add will touch at most 3 other squares, so will only require at most 4 colors to map it. Add layer after layer to infinity, similarly the criterion for 4 colors is met.
Is this what was said to be the proof?GuildCompounder (talk) 03:14, 15 December 2020 (UTC)[reply]
@GuildCompounder: Consider this ball. When you come to adding the last segment, it will touch five segments previously added. Does your method guarantee those five use no more than three colors? --CiaPan (talk) 15:47, 2 March 2021 (UTC)[reply]
The four color theorem only applies to planar maps/graphs. It's well-known (and discussed in the article) that other topologies can need more colors. I don't see the relevance to this section. --mfb (talk) 04:18, 3 March 2021 (UTC)[reply]
Sphere is equivalent to plane, actually. But McKay's original reply is correct -- building from layers of squares doesn't deal with any of the interesting maps. (And of course the observation that it sat unsolved for a century, and then required computer assistance, should be a good indication that any "simple" proof attempt is quite likely to be wrong!) Joule36e5 (talk) 05:47, 3 March 2021 (UTC)[reply]
@Mfb: Yes, other topologies can need more colors. But this is the same topology. If you exclude any point of a sphere (which may be an interior point of any "country" region, hence meaningless in map coloring), then the rest of the sphere is homeomorphic with a plane (see the Stereographic projection for an example of a continuous bijection between a punctured sphere and a plane), so any result of coloring a map on a sphere applies verbatim to a plane and vice versa. --CiaPan (talk) 10:46, 3 March 2021 (UTC)[reply]
