Some free entropy dimension inequalities for subfactors

Abstract

Suppose $N \subset M$ is an inclusion of $II_1$-factors of finite index. If $N$ can be generated by a finite set of elements, then there exist finite generating sets $X$ for $N$ and $Y$ for $M$ such that $\delta_0(X) \geq \delta_0(Y)$, where $\delta_0$ denotes Voiculescu's microstates (modified) free entropy dimension. Moreover given $\epsilon >0$ one has $\delta_0(F) \geq \delta_0(G) \geq ([M:N]^{-2} -\epsilon) \cdot (\delta_0(F) -1) + 1 - \epsilon$ for certain generating sets $F$ for $N$ and $G$ for $M$.