
Hendrik Lenstra Jr.
Tue Jan 7, 2014
3:00 pm
Given a polynomial map between two vector spaces over a field,
how many values can it miss? The lecture will present a number of
new results on this question. They were inspired by the work of
Daqing Wan, and obtained jointly with Michiel Kosters (Leiden).

JeanPierre Bourguignon
Thu Nov 7, 2013
4:00 pm
In the last century, Geometry underwent several
substantial extensions and revisions based on
the fundamental revolutions that it lived through
in the XIXth century.
The purpose of the lecture is to discuss several
aspects of these transformations: the new
concepts that emerged from these new points
of view, the new perspectives that could be...

Eitan Tadmor
Wed Jun 5, 2013
4:00 pm
We discuss selforganized dynamics of agentbased models
with focus on a prototype model driven by nonsymmetric selfalignment
introduced in [1].
Unconditional consensus and flocking emerge when the selfalignment is
driven by global interactions with a sufficiently slow decay rate. In
more realistic models, however, the interaction of...

Ravi Vakil
Thu Apr 25, 2013
4:00 pm
Given some class of "geometric spaces", we can make a ring as follows.
(additive structure) When U is an open subset of such a space X, [X] = [U] + [(X \ U)];
(multiplicative structure) [X x Y] = [X] [Y].
In the algebraic setting, this ring (the "Grothendieck ring of varieties")...

Leonid Parnovsky
Thu Apr 4, 2013
4:00 pm
I will make a survey of recent results on the spectrum of periodic and, to a smaller extent, almostperiodic operators. I will consider two types of results:
1. BetheSommerfeld Conjecture. For a large class of multidimensional periodic operators the numbers of spectral gaps is finite.
2. Asymptotic behaviour of the integrated density of states...

Fuquan Fang
Thu Jan 17, 2013
4:00 pm
There is a well known link between (maximal) polar representations and isotropy representations of symmetric spaces provided by Dadok. Moreover, the theory by Tits and BurnsSpatzier provides a link between irreducible symmetric spaces of noncompact type of rank at least three and irreducible topological spherical buildings of rank at least three...

Paul Yang
Thu Dec 6, 2012
4:00 pm
There is a good deal of resemblence of CR geometry in dimension three with conformal geometry
in dimension four. Exploiting this resemblence is quite fruitful. For instance, the presence of
several conformally covariant operators in both geometries allows us to formulate correct
conditions for the embedding problem as well as the CR Yamabe problem...