A conjecture due to M. S. Robertson (1936) which treats a Univalent Power Series containing only Odd powers within the Unit Disk. This conjecture Implies the Bieberbach Conjecture and follows in turn from the Milin Conjecture. de Branges' proof of the Bieberbach Conjecture proceeded by proving the Milin Conjecture, thus establishing the Robertson conjecture and hence implying the truth of the Bieberbach Conjecture.
See also Bieberbach Conjecture, Milin Conjecture
References
Stewart, I. From Here to Infinity: A Guide to Today's Mathematics.
Oxford, England: Oxford University Press, p. 165, 1996.