R.T. Powers has constructed a family of unital endomorphisms of the hyperfinite II1 factor R, each of which has range a subfactor of index 2, and each of which has no non-trivial invariant subalgebras ...

We study the following question: suppose that A and ℬ are two algebras of complex n × n matrices such that the ring commutator [A, B] = AB – BA is "small" for each A ∈ A and B ∈ ℬ; does this imply ...