


Algebraic geometry seminar 

Date 
Tuesday, 26 March, 11.30 am 
Venue 
Room 215 
Host 
Sudarshan Gurjar 
speaker 
Nitin Nitsure 
Affiliation 
Bhaskaracharya Pratishthana 
Title 
Galois descent and Galois cohomology: examples and calculations. 
Abstract 
We will begin by recalling the calculus of Galois descent, and its translation into Galois cohomology classes for twisted forms. After that, we will look at common examples, involving Galois twisted forms of algebraic groups, Brauer Severi varieties, and vector bundles (Hilbert 90). The final example will be the Galois twisted from over reals of a nonseparated affine line with doubled origin. This twisted form is an algebraic space which is not a scheme. 
Topology and Related Topics Seminar 

Date 
Tuesday 26 March, 2:30 pm 
Venue 
Ramanujan Hall 
Host 
Rekha Santhanam 
speaker 
Sudarshan Gurjar 
Affiliation 
IIT Bombay 
Title 
Vector bundles and Characteristic Classes 
Abstract 
This is the second talk in the series of three talks. We will give an introduction to the characteristic classes of a vector bundle. Characteristic classes are invariants of a vector bundle taking values in the singular cohomology of the base and satisfying the obvious functoriality property with respect to pullback. They are the measure of the nontriviality of the vector bundle. 
Commutative Algebra Seminar 

Date 
Tuesday, 26 March 2024, 45 pm 
Venue 
Room 215 
Host 
Tony J. Puthenpurakal 
speaker 
R. V. Gurjar 
Affiliation 
IIT Bombay 
Title 
Some more results about BrieskornPham singularitiesII 

We will discuss the following results. (1) Classification of 3dimensional factorial BP singularities by U.Storch. (2) Classification of affine BP 3folds which admit a nontrivial action of the additive group G_a (equivalently, a nonzero locally nilpotent derivation on their coordinate ring) by M. Chitayat. (3) Classification of affine BP 3folds which are rational (i.e. their function field is a purely transcendental extension of the ground field) by M Chitayat. 