Geometry Seminar


Divided difference operators in equivariant cohomology


Professor Reyer Sjamaar

Cornell University




Divided difference operators were invented by Newton for the purpose of numerical interpolation.  More recently, they showed up in work of Demazure and Bernstein-Gelfand-Gelfand on the invariant theory of compact Lie groups and the cohomology of flag varieties.  In this talk, which describe joint work with Megumi Harada, Tara Holm and Greg Landweber, I will show that they act naturally as bivariant operations in certain equivariant cohomology theories.  This leads to various computational results as well as to a more precise version of Atiyah's "splitting principle" for equivariant K-theory.



February 20, 2008 (Wednesday)


2:00 – 3:00pm


Room 517, Meng Wah Complex, HKU


Tea will be held in Room 516,  Meng Wah Complex before the lecture, at 1:45pm


All are welcome