Kerchof Hall, Room 317
3:30, Wednesday, Nov. 1

Brian Street, Princeton University, will speak on 

   Hypoellipticity and loss of derivatives

Abstract: Recently, Kohn gave an example of a sum of squares of
complex vector fields that satisfy Hormander's condition (they and
their commutators span the complexified tangent space) that is not
subelliptic.  I will discuss a parametrix construction for his
operator, and the phenomenon of hypoellipticity with a loss of
derivatives. In the process, I will discuss the connections between
hypoellipticity and Schrodinger operators.