Description
Mathematics Colloquium
Speaker: Anand Sawant.
Affiliation: School of Mathematics, TIFR.
Date and Time: Wednesday 29 January, 04:00 pm - 05:00 pm.
Venue: Ramanujan Hall, Department of Mathematics.
Title: Central extensions of algebraic groups revisited.
Abstract: The study of central extensions of a group, which began with the
work of Schur, has a long history spanning more than a hundred years.
Celebrated results of Steinberg and Matsumoto obtained about fifty years
ago determine the universal central extension of certain algebraic groups.
These results have lead to a lot of interesting developments, for
instance, the work of Brylinski and Deligne about determining the category
of central extensions of a reductive group by K_2 in terms of certain
quadratic forms. I will briefly survey these classical results and discuss
how all these results can be uniformly explained and generalized using
motivic homotopy theory. The talk is based on joint work with Fabien Morel
and will not presume any knowledge of motivic homotopy theory.