We will discuss a paper by Popa which presents a proof that any von-Neumann subalgebra of a free group factor LF_n, 2 ≤ n ≤ ∞ which has diffuse commutant in that factor is amenable.

This result was already proved by Ozawa in greater generality, but here Popa uses the properties of the free group factors to get a simpler proof.