Apéry–Fermi pencil of 𝐾3-surfaces and 2-isogenies

Abstract

Given a generic 𝐾3-surface 𝑌_𝑘 of the Apéry–Fermi pencil, we use the Kneser–Nishiyama technique to determine all its non isomorphic elliptic fibrations. These computations lead to determine those fibrations with 2-torsion sections T. We classify the fibrations such that the translation by T gives a Shioda–Inose structure. The other fibrations correspond to a 𝐾3-surface identified by its transcendental lattice. The same problem is solved for a singular member 𝑌₂ of the family showing the differences with the generic case. In conclusion we put our results in the context of relations between 2-isogenies and isometries on the singular surfaces of the family.