On the solutions of the Low equation
R. W. Lardner · Mathematical Proceedings of the Cambridge Philosophical Society · 1963
Abstract An alternative procedure is developed for examining the solutions of the Low equation. The ambiguities of those solutions which have a finite number of zeros are shown to satisfy the conditions derived earlier by Castillejo, Dalitz and Dyson. The method presented here has the advantage that it makes no special use of the positiveness of the cut-off function, and so can be used when this function changes sign. It is shown that the arbitrariness of the solution increases with the number of these sign changes, but that a completely negative cut-off function still satisfies the CDD conditions.