an important area of study in the classification of ii_1 factors is to investigate the dependence of a group von neumann algebra l(g) relative to the group g. popa’s deformation/rigidity theory has provided novel insights into this question over the past 20 years. 

in this talk, we demonstrate how one can import group cohomological information into the von neumann algebra framework to unravel the structure of a large family of von neumann algebras.