Boundedness in families with applications to arithmetic hyperbolicity

Motivated by conjectures of Demailly, Green–Griffiths, Lang and Vojta, we show that several notions related to hyperbolicity behave similarly in families. We apply our results to show the persistence of arithmetic hyperbolicity along field extensions for projective normal surfaces with non‐zero irregularity. These results rely on the mild boundedness of semi‐abelian varieties. We also introduce and study the notion of pseudo‐algebraic hyperbolicity which extends Demailly's notion of algebraic hyperbolicity for projective schemes.