Abstract
Two‐Hilbert space versions of the basic integral‐representation formulas for wave and transition operators are derived within the framework of time‐independent scattering theory. Multichannel scattering theory for state vectors as well as for statistical operators is presented in a two‐Hilbert space formulation to which these formulas become applicable. This formulation stays valid when long‐range interactions, for which renormalized wave operators exist, are present.