Donna Testerman

Donna Marie Testerman (born 1960) is a mathematician specializing in the representation theory of algebraic groups. She is a professor of mathematics at the École Polytechnique Fédérale de Lausanne in Switzerland.

Testerman completed her Ph.D. at the University of Oregon in 1985. Her dissertation, Certain Embeddings of Simple Algebraic Groups, was supervised by Gary Seitz. As a faculty member at Wesleyan University, she won a Sloan Research Fellowship in 1992.

Research

In 1992, Testerman proved that if G is a semisimple algebraic group over an algebraically closed field k of characteristic p and p is a good prime for G, and u is an element of G satisfying , then there exists a subgroup X of G which is isomorphic to the special linear group or to the projective special linear group . Testerman also proved a variant theorem where one may take a surjective endomorphism that fixes u, and conclude that . In particular, there are only finitely many such conjugacy classes, except in the case where X is D4, G is E7, and the characteristic is 2.