Let A,B⊆ewlineZA,B \subseteq ewline \mathbb ZA,B⊆ewlineZ be nonempty, and let F=(Fn)n∈N\mathbf F=(F_n)_{n\in\mathbb N}F=(Fn)n∈N be a Følner sequence of finite subsets of Z\mathbb ZZ, meaning that … for every…
