An approach to the study of boundary actions

Given an action of a discrete countable group $G$ on a countable set $\mathfrak{X}$, it is studied the relationship between properties of the associated Calkin representation and the dynamics of the group action on the boundary of the Stone-\v{C}ech compactification of $\mathfrak{X}$. The first section contains results about amenability properties of actions of discrete countable groups on non-separable spaces and is of independent interest. In the second section these results are applied in order to translate regularity properties of the Calkin representation and the topological amenability on the Stone-{\v C}ech boundary within the common framework of measurable dynamics on certain extensions of the Stone-{\v C}ech boundary of $\mathfrak{X}$.