Følner, Banach, and translation density are equal and other new results about density in left amenable semigroups

Daniel Glasscock, Neil Hindman, Dona Strauss

In any semigroup $S$ satisfying the Strong Folner Condition, there are three natural notions of density for a subset $A$ of $S$: Folner density $d(A)$, Banach density $d^{\ast }(A)$, and…