We prove that has no proper superstable expansions of finite Lascar rank. Nevertheless, this structure equipped with a predicate defining powers of a given natural number is superstable of Lascar rank . Additionally, our methods yield other superstable expansions such as equipped with the set of factorial elements.
"On Superstable Expansions of Free Abelian Groups." Notre Dame J. Formal Logic 59 (2) 157 - 169, 2018. https://doi.org/10.1215/00294527-2017-0023