Prather, Carl L.2017-09-182017-09-181981-01-01C. L. Prather, “Note on a role for entire functions of the classes and ,” International Journal of Mathematics and Mathematical Sciences, vol. 4, no. 4, pp. 649-654, 1981. doi:10.1155/S0161171281000483http://hdl.handle.net/10919/79126We use the B and B* operators of Levin on the Classes P and P* and a comparison principle to prove a Gauss-Lucas Theorem for differential operators. The connection with the determination of final sets for differential operators is then clarified.application/pdfenCreative Commons Attribution 4.0 InternationalArticle - Refereed2017-09-18Copyright © 1981 Hindawi Publishing Corporation. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.https://doi.org/10.1155/S0161171281000483