Electronic Journal of Differential Equations Vol. 1993 (1993) No. 01, pp.1-7. Title: Lie Generators for Semigroups of Transformations on a Polish Space Authors: J. R. Dorroh (Louisiana State Univ., Baton Rouge, LA, USA) John W. Neuberger (Univ. of North Texas, Denton, TX, USA) Abstract: Let $X$ be a separable complete metric space. We characterize completely the infinitesimal generators of semigroups of linear transformations in $C_b(X)$, the bounded real-valued continuous functions on $X$, that are induced by strongly continuous semigroups of continuous transformations in $X$. In order to do this, $C_b(X)$ is equipped with a locally convex topology known as the {\it strict topology. } Submitted May 8, 1993. Published August 27, 1993. Math Subject Classification: 47H20, 47D20. Key Words: Semigroups of operators; infinitesimal generator. ~