We consider a spherical bowl without any great circle. The distance between points A and B on such a bowl is defined as the length of the arc of the great circle of the sphere with ends at points A and B, which is contained in the bowl. Prove that there is no isometry mapping this bowl to a subset of the plane.Attention. A spherical bowl is each of the two parts into which the surface of the sphere is divided by a plane intersecting the sphere. geometry3D geometryspherecombinatorial geometry