Thu, 21 Jan 2016
12:00
L6

Obstacle problems of Signorini type, and for non-local operators

Nicola Garofalo
(Universita' degli studi di Padova)
Abstract
In this talk I will overview what is presently known about various types of obstacle problems. The focus will be on elliptic and parabolic problems of Signorini type, and on problems for non-local operators. I will discuss the role of monotonicity formulas in such problems, as well as (in the time-independent case) of some new epiperimetric inequalities. 
Thu, 18 Feb 2016

14:00 - 15:00
L5

Ten things you should know about quadrature

Professor Nick Trefethen
(Oxford)
Abstract

Quadrature is the term for the numerical evaluation of integrals.  It's a beautiful subject because it's so accessible, yet full of conceptual surprises and challenges.  This talk will review ten of these, with plenty of history and numerical demonstrations.  Some are old if not well known, some are new, and two are subjects of my current research.

Tue, 26 Jan 2016

14:15 - 15:30
L4

Extensions of modules for graded Hecke algebras

Kei Yuen Chan
(Amsterdam)
Abstract

Graded affine Hecke algebras were introduced by Lusztig for studying the representation theory of p-adic groups. In particular, some problems about extensions of representations of p-adic groups can be transferred to problems in the graded Hecke algebra setting. The study of extensions gives insight to the structure of various reducible modules. In this talk, I shall discuss some methods of computing Ext-groups for graded Hecke algebras.
The talk is based on arXiv:1410.1495, arXiv:1510.05410 and forthcoming work.

Tue, 23 Feb 2016

14:15 - 15:30
L4

Discrete triangulated categories

David Pauksztello
(Manchester)
Abstract
This is a report on joint work with Nathan Broomhead and David Ploog.
 
The notion of a discrete derived category was first introduced by Vossieck, who classified the algebras admitting such a derived category. Due to their tangible nature, discrete derived categories provide a natural laboratory in which to study concretely many aspects of homological algebra. Unfortunately, Vossieck’s definition hinges on the existence of a bounded t-structure, which some triangulated categories do not possess. Examples include triangulated categories generated by ‘negative spherical objects’, which occur in the context of higher cluster categories of type A infinity. In this talk, we compare and contrast different aspects of discrete triangulated categories with a view toward a good working definition of such a category.
 

 
Tue, 01 Mar 2016

14:15 - 15:30
L4

There And Back Again: A Localization's Tale.

Sian Fryer
(Leeds)
Abstract

The prime spectrum of a quantum algebra has a finite stratification in terms
of a set of distinguished primes called H-primes, and we can study these
strata by passing to certain nice localizations of the algebra.  H-primes
are now starting to show up in some surprising new areas, including
combinatorics (totally nonnegative matrices) and physics, and we can borrow
techniques from these areas to answer questions about quantum algebras and
their localizations.    In particular, we can use Grassmann necklaces -- a
purely combinatorial construction -- to study the topological structure of
the prime spectrum of quantum matrices.

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