Infinite unrestricted sumsets in subsets of abelian groups with large density

Dimitrios Charamaras, Ioannis Kousek, Andreas Mountakis +1

Let $(G,+)$ be a countable abelian group such that the subgroup $\{g+g:g\in G\}$ has finite index and the doubling map $g\mapsto g+g$ has finite kernel. We establish lower bo…