Parametrization of N D input

A modified version of the usual single channel N/D equations is presented, which makes possible a mathematically sound parametrization of the effect of those distant parts of the left hand cut and right hand cut for which the discontinuities are not known. A conformal mapping technique is used to develop a generally valid parametrization involving only real parameters. An application to the Phillips plot of triton energy versus doublet scattering length is given so as to demonstrate the superiority of the present scheme over ones used earlier by us.