3-D continued fractions - MathOverflow most recent 30 from http://mathoverflow.net2013-05-18T13:36:34Zhttp://mathoverflow.net/feeds/question/111791http://www.creativecommons.org/licenses/by-nc/2.5/rdfhttp://mathoverflow.net/questions/111791/3-d-continued-fractions3-D continued fractionsBoris Frolov2012-11-08T08:18:38Z2012-11-08T08:41:48Z
<p>Which theorems from classical theory of continued fractions have 3-(or multi-) dimesional analogs?</p>
<p>Of cause classical one is a periodicity of Klein polyhedra. Probably there are some more...</p>
http://mathoverflow.net/questions/111791/3-d-continued-fractions/111793#111793Answer by Alexey Ustinov for 3-D continued fractionsAlexey Ustinov2012-11-08T08:24:52Z2012-11-08T08:41:48Z<p>(1) There is 3-D analog of Vahlen's theorem, see <a href="http://link.springer.com/article/10.1007%2Fs11006-006-0018-6?LI=true" rel="nofollow">http://link.springer.com/article/10.1007%2Fs11006-006-0018-6?LI=true</a></p>
<p>(2) 3-D isolation theorems and extemal Davenport forms (see Cassels "An Introduction to the Geometry of Numbers" and Swinnerton-Dyer, "On the product of three homogeneous linear forms" Acta Arith., 1971, 18, 371-385). The key role here play numbers $2\cos\frac{2\pi}7$, $2\cos\frac{4\pi}7$, $2\cos\frac{6\pi}7$ (3-D Golden Ratios).</p>