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Convex disks can cover their shadow

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Abstract

We give a short proof of the fact that given any two-dimensional convex disk in three-space and an orthogonal projectionC′ ofC on a plane then there is a congruent copy ofC which containsC′.

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    H. E. Debrunner and P. Mani-Levitska, Can you cover your shadows?,Discrete & Computational Geometry,1 (1986), 45–58.

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Kós, G., Törőcsik, J. Convex disks can cover their shadow. Discrete Comput Geom 5, 529–531 (1990). https://doi.org/10.1007/BF02187808

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Keywords

  • Orthogonal Projection
  • Parallel Line
  • Discrete Comput Geom
  • Convex Compact
  • Computational Geometry