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Apr 13, 2017 at 12:58 history edited CommunityBot
replaced http://mathoverflow.net/ with https://mathoverflow.net/
Jan 26, 2017 at 0:23 history edited Stefan Kohl CC BY-SA 3.0
Updated image links.
Jul 28, 2014 at 10:08 history edited Stefan Kohl CC BY-SA 3.0
Added a link to a video showing additional pictures of spheres under the action of G on Z^2.
Apr 15, 2014 at 18:16 comment added vzn this appears to be a case of what are known by some as "collatz like functions". eg sec 1.4 & others of new/recent paper Problems in number theory from busy beaver competition by Michel. basically these problems are difficult to study & lie at the boundary of decidable and undecidable & are an open/active area of research.
Mar 17, 2014 at 14:32 answer added Sebastien Palcoux timeline score: 11
Mar 17, 2014 at 11:31 comment added Sebastien Palcoux What beautiful pictures! An animation showing successively all the spheres from radius 0 to radius 45 would be interesting too: one animation with a fixed scale, and one with a renormalized scale. Do you observe that the shape of the spheres (at renormalized scale) "converge" to a (unique) fractal shape (I hope my question is understandable) ?
Mar 16, 2014 at 22:39 history edited Stefan Kohl CC BY-SA 3.0
Added a picture of the sphere of radius 45 about (0,0) under the action of G at a scale of about 1:100, as well as links to pictures of the spheres of radius 30 and 36.
Mar 14, 2014 at 18:45 comment added Sebastien Palcoux Besides the fractal structure, the spheres look like to an explosion, I had never seen such pattern in pure mathematics. I don't know if there is something to say mathematically about that, perhaps such group actions appear in a discrete modelling of physical explosions.
Mar 12, 2014 at 21:34 history edited Stefan Kohl
Added tags ds.dynamical-systems and fractals, following Sebastien Palcoux' suggestion.
Mar 12, 2014 at 12:51 comment added Sebastien Palcoux Why don't you put the tags ds.dynamical-systems and fractals ? Experts of these subjects could help you (there are others fractal-like phenomenons on discrete strutures, for example the Rauzy fractals).
Mar 12, 2014 at 2:48 comment added Noah Schweber This is a wonderful question!
Mar 11, 2014 at 20:50 history edited Stefan Kohl CC BY-SA 3.0
Added list of cardinalities of spheres of radii 0 .. 45.
Mar 11, 2014 at 20:36 comment added Stefan Kohl @PerAlexandersson: see my comment below your answer.
Mar 11, 2014 at 20:00 comment added Per Alexandersson Hm, what do you mean by the sphere here? You are looking at the forward orbit of (0,0) under all maps, are you not?
Mar 11, 2014 at 19:26 answer added Per Alexandersson timeline score: 3
Mar 11, 2014 at 18:33 history asked Stefan Kohl CC BY-SA 3.0