Billiards in ellipses revisited
By A. Akopyan, Richard Evan Schwartz, Serge Tabachnikov. European Journal of Mathematics, 2020
49 citations recorded by the source corpus.
We prove some recent experimental observations of Dan Reznik concerning periodic billiard orbits in ellipses. For example, the sum of cosines of the angles of a periodic billiard polygon remains constant in the 1-parameter family of such polygons (that exist due to the Poncelet porism). In our proofs, we use geometric and complex analytic methods.
Subfields: Geometry and Topology, Mathematical Physics, Statistical and Nonlinear Physics
View Paper: https://www.semanticscholar.org/paper/962bb277a41b28ac416868dae62460f23c87226e
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In Geometry and Topology
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Citations in the corpus
- Dan Reznik’s identities and more (2020, methodology): “e h( ) = 1=‘= q a2 1 cos2 + a2 2 sin 2 , as claimed. The billiard in ellipse is integrable, and the conserved quantity, called the Joachimsthal integral, is, in the above notation, jNjsin(see [6] or [2]). This can be written as J= sin( ) h( ) : This means that, along an invariant curve of the billia”