Talk:Arnold tongue

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Title[edit]

Great article; I learnt that Arnol'd tongues can in fact be described in very simple language. However, I have the distinct impression that "circle map" refers to any map from the circle to itself. I think the map described here is usually called the "sine circle map" (though I've also seen "sine map"). -- Jitse Niesen (talk) 11:52, 19 January 2006 (UTC)

I think the chaos literature is pretty consisent in using "circle map" to refer to only this map, although I've seen the more general definition on occasion. The only support I have for this at the moment is the MathWorld article, and the refs that it cites. linas 23:36, 19 January 2006 (UTC)
I agree with Nitse. A "circle map" can be any map of the circle. The confusion might come from the fact that the standard maps described by Arnol'd essentially model the behavior of many circle maps, up to topological conjugacy.

Renamed[edit]

I renamed article to Arnold tongues per the discussion above. The term circle map can certainly refer to any map of a circle, and there are various researches devoted to study of circle maps, see e.g. Katok-Hasselblat. The family exposed can be named standard circle maps family or something like this, but I believe Arnold tongues is the main subject of the paper. Ilya Voyager (talk) 15:52, 5 September 2012 (UTC)

....and I changed it to Arnold tongue since WP:MOS clearly says the singular should be used except when there's a reason to use the plural. Michael Hardy (talk) 03:56, 6 September 2012 (UTC)

Beating heart model[edit]

How does the circle map correspond to a model of the beating heart? If this could be explained briefly and in language suitable for a layman, possibly in a section of its own (near the end of the article?), that would be excellent. --Quuxplusone 17:14, 16 April 2006 (UTC)

Who is the eponym??[edit]

Is this named after Vladimir Arnold? If not, who's it named after? It is unconscionable that that question is not answered. It should be in the first line. Michael Hardy (talk) 04:11, 6 September 2012 (UTC)

For those who haven’t seen - see WP Maths. Maschen (talk) 16:39, 6 September 2012 (UTC)
Yes, Its VI Arnold. linas (talk) 19:32, 11 September 2012 (UTC)

link to text-book please[edit]

Can't understand the article... where to go to get the basics first... can't Wikipedia have this section "textbook / prerequisites" for all mathematical/technical articles. 117.198.121.106 (talk) 08:42, 27 October 2012 (UTC)

Second Image[edit]

In the second image, with the subtitle "Some of the Arnold tongues for the standard circle map, ", shouldn't alpha by Omega on the horizontal axis? And the comma a period in the subtitle? — Preceding unsigned comment added by Mmbosschaert (talkcontribs) 16:33, 20 January 2013 (UTC)

Circle map redirect[edit]

Could we remove the redirect from circle map to this? It doesn't explain what a circle map is.98.150.246.242 (talk) 07:19, 14 February 2014 (UTC)

How does it not explain what a circle map is? It's the first section. Eflatmajor7th (talk) 21:35, 15 February 2014 (UTC)

Rotation Number[edit]

The rotation number in this article looks strange to me or simply wrong, so to say, though I might be wrong. Compare the expression with the rotation number article: https://en.wikipedia.org/wiki/Rotation_number Simply put, the rotation number is something like an average rotation angle per iteration. In this article's formula, however, there is a sum over all angles theta_n. For example, if we set K = 0, we should obtain Omega as the rotation number. For K = 0, we should have something like theta_n = n * Omega. If we put this in the sum of the numerator, we get something like 1/2 * n * (n+1) * Omega and thus, the limit n --> infinity does not exist. Without the sum, however, everthing is right, since we immediately get omega = Omega. Without the sum, the formula would also be consistent with the one in the rotation number article if we choose theta_0 = 0 (which we can do, since the number is proven to be independent of the starting angle, see the other article). I also checked some of the sources for this specific expression, but I didn't find anything similar. In fact, all the definitions of the rotation number in the sources are the same as in the Rotation Number article. I therefore suggest to simply remove the sum. But if I am wrong, you may correct me, which is my I didn't change anything yet. 178.20.90.65 (talk) 19:14, 18 February 2016 (UTC)

I would encourage you to make the change(s) you think is/are necessary. No one has been checking up on this page in quite a while. Your explanation for what you want to do sounds right to me. Eflatmajor7th (talk) 03:26, 19 February 2016 (UTC)