Wave operators for the linearized Boltzmann equation in one-speed transport theory

A dissipative integro-differential operator L arising in the linearization of Boltzmann's equation in one-speed particle transport theory is considere d. Under assumptions ensuring that the point spectrum of L is finite a scal ar multiple of the characteristic functions of L is found and a condition f or the absence of spectral singularities is indicated. Using the techniques of non-stationary scattering theory and the Sz.-Nagy-Foias functional mode l direct and inverse wave operators with the completeness property are cons tructed. The structure of the operator L in the invariant subspace correspo nding to its continuous spectrum is studied.