Existence of Solutions of N/D Equations

The manifold of solutions of certain classes of N/D equations is considered, under the restriction that the scattering amplitude have a uniform bound in all complex directions. Two cases are treated: (i) The N integral equation is Fredholm, but the associated homogeneous equation may have solutions; (ii) the equation has the marginally singular behavior characteristic of an asymptotically constant left-hand cut discontinuity. The existence theorem in the latter case proceeds by the construction of the appropriate resolvent.