Leibniz ; Ph.D. thesis: Dissertatio Algebraica de Algorithmo Infinitesimali Differentiali (Dissertation on the algebra of solving differential equations using infinitesimals) , University of Leipzig, 1704 Christian Wolff was professor of mathematics and natural philosophy at the University of Halle 1706 - 1723 and 1740 - 1754 and at Marburg 1723 - 1740.