Algebraic approach to some propagation properties of the Schroedinger equation

We describe a criterion which allows to deduce that a self-adjoint operator H has the following properties in some neighborhood (E-delta, E+delta) of E <- Bsub(c)(H): 1) The point spectrum is discret in (E-delta, E+delta). 2) There is no singular continuous spectrum. 3) In any interval [a,b] c (E-delta, E+delta)/Bsub(p)(H) the resolvant (H-Z)-1 satisfies three kinds of a 'Priori Estimates', connected with properties of the propagation esup(-iHt). (orig./HSI)