Automorphism groups of rational elliptic and quasi-elliptic surfaces in all characteristics

Abstract

We study the groups of automorphisms of rational algebraic surfaces that admit a relatively minimal pencil of curves of arithmetic genus one over an algebraically closed field of arbitrary characteristic. In particular, we classify such surfaces that admit non-trivial automorphisms that act trivially on the Picard group. As an application, we classify classical Enriques surfaces in characteristic $2$ that admit non-trivial numerically trivial automorphisms.

38 pages, v2: Lemma 6.6 fixed, updated Table 3, 4 accordingly