Reversibility and regularity

The Zeno problem of quantum mechanical measurement theory is revisited. A fundamental underlying domain issue is clarified. An alternative formulation for the Zeno problem is given. A new operator-theoretic characterization of reversibility in terms of domain regularity preservation is announced. From these considerations one arrives at a new perspective in which von Neumann's Projection theory and the later Effects theory of Ludwig are seen within an enlarged theory of Measurors and Preparors. It is a Schrodinger picture in which one must be able to account for all wave functions upon which the Hamiltonian can act before one is entitled to draw conclusions about the evolving probabilities.