Tzitzeica curves and surfaces represent early examples of affine-invariant geometrical objects. At the time Gheorghe Tzitzeica was studying these objects, affine differential geometry (ADG) was in its infancy. ADG was motivated by Felix Klein’s influential Erlangen program, where a geometry was defined by its set of invariants under a group of symmetries. We find that … Continue reading Tzitzeica Curves and Surfaces