Date & Time: Friday, September 7, 2012, 16:30-17:30.

Venue: Room No. 216 (Mathematics Dept. 2nd Floor)

Title:Nice group structure on relative orbit space of unimodular rows.

Speaker: Prof. Anuradha Garge, CBS Mumbai.

Abstract:The orbit space of unimodular rows under the action of the elementary subgroup of the general linear group admits a group structure depending on the dimension of the ring and the length of unimodular rows. This group structure was first defined by Vaserstein in case of length 3 and extended inductively by van der Kallen to length greater than 3. The formula for this group structure is complicated.

That the group structure has a simpler and ``nicer'' formula depending on the ring and its dimension was shown in the absolute case. These results are extended to the relative case too. This is joint work with Ravi Rao.