Monday, January 10, 1600-1700 |
Speaker :
Boris Shapiro, Stockholms Universität.
Title : James Maxwell on critical points of a system of point charges
Abstract
:
Monday, January 24, 1600-1700 |
Speaker :
Volodymyr Mazorchuk, Uppsala.
Title : Categorification - a new idea in algebra and topology.
Abstract
:In this talk I would like to describe the relatively
new idea of categorification, which was formulated for the first
time by M. Khovanov a couple of years ago. This idea is now rather
popular, intensively studied and widely used, in particular, in
algebra and topology. In contrast to the usual mathematical
practice of "making things easier", categorification is actually
an idea to "make things more complicated", for example to upgrade
a positive integer to a vector space, or a vector space to a
category. The point is that sometimes this allows one to get
more information, wich was not visible on the original level.
.
Monday, February 7, 1600-1700 |
Speaker :
Giuseppe Toscani, Pavia.
Title : Overpopulated tails in nonconservative kinetic systems.
Abstract
:To be announced.
.
Monday, February 28, 1600-1700 |
Speaker :
Christian Krattenthaler, Universität Wien.
Title : Exact and asymptotic enumeration of watermelons with a wall interaction.
Abstract
:I consider an instance of the vicious walker model of Michael
Fisher, proposed by Owczarek, Essam and Brak, in which their is an
interaction of the walkers with a fixed wall. I show how to completely
solve the problem of determining the asymptotic behaviour of the
corresponding partition function (and of another interesting parameter).
In the course of doing that, we shall meet some of my deer friends:
determinants, a tableau bijection, and hypergeometric series..
.
Monday, March 21, 1600-1700. |
Speaker :
Gerhard Rein, University of Bayreuth (Germany).
Title : Nonlinear stability of Newtonian galaxies and stars.
Abstract
:
In astrophysics, the dynamics of a galaxy is often
modelled by the Vlasov or collisionless Boltzmann equation
coupled to the Poisson equation. We will show that certain steady
states of this system are minimizers of so-called energy-Casimir
functionals. From this fact the nonlinear stability of these steady
states can be derived.
The approach is such that it yields as a bonus also the nonlinear
stability of barotropic stars described
as steady states of the Euler-Poisson system.
Monday, May 16, 1600-1700 (OBS! NEW DATE FOR THE SECOND TIME) |
Speaker :
Viktor Berbyuk, Mechanical Engineering, Chalmers.
Title : Control and optimization of semi-passively actuated mechatronic systems.
Abstract
: here.
.
Monday, May 23, 1600-1700 |
Speaker :
Sergey Kislyakov, PDMI, St. Petersburg
Title : Stability of approximation under singular integral operators and Calderon-Zygmund type decompositions.
Abstract
:
In their classical paper "On existence of certain singular integrals"
(Acta Math., 88 (1952), 85-139), Calderon and Zygmund used quite
efficiently a simple procedure of splitting a function in a "good" and
"bad" part. Since then, this procedure has been reproduced in many
textbooks; moreover, many related constructions suitable for other
purposes have been invented. For example, it is fairly well known by now
that for many spaces of $X$ "smooth" functions (like $Lip_\alpha$, or
Sobolev classes, or BMO), a specific Calderon-Zygmund type algorithm can
be used to exhibit an element $u$ of almost optimal $L^1$-approximation of
a given function $f\in L^1$ by a ball of a fixed radius in $X$.
The main new result of the talk sais that for most of the singular
integral operators $T$ the function $Tu$ also approximates $Tf$ in the
same $L^1$-optimal sense provided $Tf$ is integrable.
This is a part of a joint work with N. Kruglyak
.
Monday, May 30, 1600-1700. |
Speaker :
Andrei Toom, Universidade Federal de Pernambuco (Brazil).
Title : Geometrical methods in cellular automata.
Abstract
:
To be announced.
Tuesday, June 7, 1600-1700 (OBS! TUESDAY) |
Speaker :
Mihai Ciuci, Georgia Tech.
Title : A random tiling model for
two-dimensional electrostatics.
Abstract
:
We consider random lozenge tilings with a finite number of
triangular holes. We define the correlation of such holes by including
them in large lattice regions and considering an appropriate normalization
of the number of tilings of the complement of the holes. We show that in
the scaling limit the correlation is obtained from a multiplicative
superposition principle that parallels two dimensional electrostatics. Our
results apply or any finite collection of lattice triangular holes of even
side. We also indicate how a lattice refinement parameter accounts for
physical temperature.