Theodore Frankel  Theodore Frankel (June 17, 1929 – August 5, 2017) was a mathematician who introduced the Andreotti–Frankel theorem. Frankel received his Ph.D. from the University of California, Berkeley in 1955. His doctoral advisor was Harley Flanders. A Professor Emeritus of Mathematics at University of California, San Diego, Frankel was a longtime member of the Institute for Advanced Study in Princeton, New Jersey. He is known for his work in global differential geometry, Morse theory, and relativity theory. He joined the UC San Diego mathematics department in 1965, after serving on the faculties at Stanford University and Brown University.