Automorphisms mapping a point into a subvariety

Abstract

The problem of deciding, given a complex variety X, a point x \in X, and a subvariety Z \subseteq X, whether there is an automorphism of X mapping x into Z is proved undecidable. Along the way, we prove the undecidability of a version of Hilbert's tenth problem for systems of polynomials over Z defining an affine Q-variety whose projective closure is smooth.