An extension of Haagerup's reduction theorem with applications to subdiagonal subalgebras of general von Neumann algebras

Louis Labuschagne, Quanhua Xu

We revisit Haagerup's enigmatic reduction theorem \cite[Theorems 2.1 \& 3.1]{HJX} showing how that theorem may be extended to general von Neumann algebras $\M$ equipped with an arb…