Emmy Noether Lectures

2020 Lecturer: Birgit Späh

Branching Laws for Representations of Non Compact Orthogonal Groups

Brief Biography:
Birgit Speh is the Goldwin Smith Professor of Mathematics at Cornell University. She received
her Ph.D. from MIT in 1977, under the supervision of Bertram Kostant. She held postdoctoral
positions at the University of Chicago and the University of Wuppertal before joining the faculty
at Cornell University in 1980. In 1983 she became the first woman to earn tenure in the Cornell
University Department of Mathematics.
Speh has been the recipient of many honors and awards, including a Sloan Fellowship in 1981
and a Humboldt Research Award in 1996. In 2006 she was an invited speaker at the
International Congress of Mathematicians in Madrid.  She was in the Inaugural Class of Fellows
of the American Mathematical Society in 2013.
Birgit Speh is known for her work on the representation theory of reductive Lie groups, and its
relationship to automorphic forms and the cohomology of arithmetic groups. In her thesis she
classified the unitary representations of low dimensional general linear groups and then
introduced in her early work  a special class of unitary representations of general linear groups
over the real numbers,  that now bears her name. Speh’s research over the years has explored
connections between unitary representations, automorphic forms, and the geometry of locally
symmetric spaces. In recent work Speh has studied restrictions of representations of reductive
groups to non-compact reductive subgroups. This work on “symmetry breaking” has led, in joint
work with Kobayashi, to proofs of conjectures of Gross-Prasad for some pairs of orthogonal
groups.  Speh has made outstanding research contributions for over 40 years.