Infinite multiplicity of abelian subalgebras in free group subfactors
arXiv:math/0402107
Abstract
We obtain an estimate of Voiculescu's (modified) free entropy dimension for generators of a -factor $\mc{M}$ with a subfactor $\mc{N}$ containing an abelian subalgebra $\mc{A}$ of finite multiplicity. It implies in particular that the interpolated free group subfactors of finite Jones index do not have abelian subalgebras of finite multiplicity or Cartan subalgebras.