Ramsey properties of subsets of $\mathbb{N}$

Abstract

We associate ergodic properties to some subsets of the natural numbers. For any given family of subsets of the natural numbers one may study the question of occurrence of certain "algebraic patterns" in every subset in the family. By "algebraic pattern" we mean a set of solutions of a system of diophantine equations. In this work we investigate a concrete family of subsets - WM sets. These sets are characterized by the property that the dynamical systems associated to such sets are "weakly mixing", and as such they represent a broad family of randomly constructed subsets of (\mathbb{N}). We find that certain systems of equations are solvable within every WM set, and our subject is to learn which systems have this property. We give a complete characterization of linear diophantine systems which are solvable within every WM set. In addition we study some non-linear equations and systems of equations with regard to the question of solvability within every WM set.