An equichordal characterization of the ellipsoid and the sphere

Victor A. Aguilar-Arteaga, Rafael Iván Ayala-Figueroa, Jesús Jerónimo-Castro +1

Let $K$ and $L$ be two convex bodies in ${\mathbb{R}}^n$, $n\ge 3$, with $L\subset \text{int}K$. In this paper we prove the following result: if every two parallel chords of $K$,…