Extreme extensions of positive operators
Associated with every vector measure m taking its values in a Fréchet space X is the space L1(m) of all m-integrable functions. It turns out that L1(m) is always a Fréchet lattice. We show that possession of the AL-property for the lattice L1(m) has some remarkable consequences for both the underlying Fréchet space X and the integration operator f → ∫ f dm.
Let be a Jordan-Banach algebra with identity 1, whose norm satisfies:(i) , (ii) (iii) . is called a JB algebra (E.M. Alfsen, F.W. Shultz and E. Stormer, Oslo preprint (1976)). The set of squares in is a closed convex cone. is a complete ordered vector space with as a order unit. In addition, we assume to be monotone complete (i.e. coincides with the bidual ), and that there exists a finite normal faithful trace on .Then the completion of with respect to the Hilbert structure...