OP-00969 Open Cocycle superrigidity of Bernoulli actions of groups with vanishing first ℓ²-Betti number OA · Bernoulli actions · cocycle superrigidity · ℓ²-Betti numbers · Peterson's operator algebra problems
OP-00970 Open Trivial fundamental group for Bernoulli crossed products OA · Bernoulli actions · fundamental group of II₁ factors · ℓ²-Betti numbers · Peterson's operator algebra problems
OP-00973 Open Cost of a group and its first ℓ²-Betti number GR · cost · ℓ²-Betti numbers · measured group theory · Peterson's operator algebra problems
OP-00979 Open Unique Cartan subalgebras for groups with a nonzero ℓ²-Betti number OA · Cartan subalgebras · C-rigidity · ℓ²-Betti numbers · Peterson's operator algebra problems