Displaying similar documents to “Integrable smooth planar billiards and evolutes.”

The centre symmetry set

Peter Giblin, Paul Holtom (1999)

Banach Center Publications

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A centrally symmetric plane curve has a point called it’s centre of symmetry. We define (following Janeczko) a set which measures the central symmetry of an arbitrary strictly convex plane curve, or surface in R 3 . We investigate some of it’s properties, and begin the study of non-convex cases.

Parallelograms inscribed in a curve having a circle as π/2-isoptic

Andrzej Miernowski (2008)

Annales UMCS, Mathematica

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Jean-Marc Richard observed in [7] that maximal perimeter of a parallelogram inscribed in a given ellipse can be realized by a parallelogram with one vertex at any prescribed point of ellipse. Alain Connes and Don Zagier gave in [4] probably the most elementary proof of this property of ellipse. Another proof can be found in [1]. In this note we prove that closed, convex curves having circles as π/2-isoptics have the similar property.

Notes on geometry

Heinrich W. Guggenheimer (1969)

Archivum Mathematicum

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