Equichordal point problem

Resolved problem in plane geometry

In Euclidean plane geometry, the equichordal point problem is the question whether a closed planar convex body can have two equichordal points. The problem was originally posed in 1916 by Fujiwara and in 1917 by Wilhelm Blaschke, Hermann Rothe, and Roland Weitzenböck. A generalization of this problem statement was answered in the negative in 1997 by Marek R. Rychlik.

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