Lecture series on algebraic stacks
Friday 20 October, 11.30 am

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Venue: Ramanujan Hall
Host: Sudarshan Gurjar

Speaker: Nitin Nitsure

Affiliation: TIFR, Mumbai (Retd)

Title: Examples of Algebraic Stacks
Abstract:  This lecture will present various basic examples and 
non-examples of algebraic stacks. These examples are useful in 
applications, and they also serve to better understand the definitions
 

Mathematics Colloquium

Friday, 20 Oct. 4 pm

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Venue: Ramanujan Hall

Host: Ravi Raghunathan

Speaker: Dinakar Ramakrishnan

Affiliation: California Institute of Technology

Title: Abelian 3-folds of Picard type, and a uniform irreducibility 
result

Abstract: Half a century ago Manin proved a uniform boundedness result 
for the p-power torsion of any non-CM elliptic curve E over a given 
number field k. A few years ago, Cadoret and Tamagawa established a  
similar result for the p-adic representations attached to 1-dimensional 
abelian families. In joint work with M. Dimitrov, we provide the 1st 
evidence in higher dimension, for families of abelian 3-folds 
parametrized by certain Picard modular _surfaces_. The proof also 
involves aspects of  (global and local) representation theory.

Coding Theory Seminar

Friday, 20th Oct.,  5.15 pm

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Venue: Ramanujan Hall

Host: Sudhir Ghorpade

Speaker: Prof. Trygve Johnsen

Affiliation: Arctic University of Norway=

Title: Homological and combinatorial invariants of rank-metric codes

Abstract:  We will look at some similarities and differences between the 
behavior of (traditional) linear codes with the Hamming distance, and 
Gabidulin rank metric codes.  We will study how methods for determining 
the spectra and invariants of traditional codes can, or cannot, be 
"transferred" to studying analogous properties of the rank-metric codes.