On a canonical lattice structure on the effect algebra of a von Neumann   algebra
  Let R be a von Neumann algebra acting on a Hilbert space H and let R_sa be the set of selfadjoint elements of R. It is well known that R_sa is a lattice with respect to the usual partial order &#8804; if and only if R is abelian. We define and study a new partial order on R_sa, the spectral order &#8804;_s, which extends &#8804; on projections, is coarser than the usual one, but agrees with it on abelian subalgebras, and turns R_sa into a boundedly complete lattice. The effect algebra E(R) := {A | 0 &#8804; A &#8804; I} is then a complete lattice and we show that the mapping A --> R(A), where R(A) denotes the range projection of A, is a homomorphism from the lattice E(R) onto the projection lattice P(R) of A if and only if R is a finite von Neumann algebra. 
Hans F. de Groote