Geometry and Topology

Speaker: Agnes Beaudry (Univ. of Chicago)

"Finite Resolutions and K(2)-Local Computations"

Time: 15:30

Room: MC 107

The chromatic filtration of stable homotopy breaks calculations one prime at a time and one level at a time. At chromatic level 2, finite resolutions of the K(2)-local sphere, have been a successful tool for computations. I will explain how to use such resolutions to do computations at the prime 2.

Geometry and Topology

Speaker: Victor Snaith (Sheffield)

"The bar-monomial resolution and applications to automorphic representations"

Time: 13:30

Room: MC 108

Admissible representations of locally $p$-adic Lie groups and automorphic representations of adelic Lie groups are important ingredients in modern number theory. This is because of their deep relationship to modular forms, L-series and Galois representations. This talk will explain how to construct these representations as objects (monomial resolutions) in a (non-abelian) derived category. This construction applies to representations defined over an algebraically closed field of any characteristic. The intended advantage of this point of view lies in the fact that in this derived category L-series and base base change have elementary descriptions.

Analysis Seminar

Speaker: Vassili Nestoridis (University of Athens)

"Universality and regularity of the integration operator"

Time: 15:30

Room: MC 108

Let $Y$ denote the space of holomorphic functions in a planar domain $\Omega$, such that the derivatives of all orders extend continuously to the closure of $\Omega$ in the plane $\mathbb{C}$. We endow $Y$ with its natural topology and let $X$ denote the closure in $Y$ of all rational functions with poles off the closure of $\Omega$. Some universality results concerning Taylor series or Pade approximants are generic in $X$. In order to strengthen the above results we give a sufficient condition of geometric nature assuring that $X$=$Y$. In addition to this, if a Jordan domain $\Omega$ satisfies the above condition, then the primitive $F$ of a holomorphic function $f$ in $\Omega$ is at least as smooth on the boundary as $f$, even if the boundary of $\Omega$ has infinite length. This led us to construct a Jordan domain $\Omega$ supporting a holomorphic function $f$ which extends continuously on the closure of $\Omega$, such that its primitive $F$ is even not bounded in $\Omega$. Finally we extend the last result in generic form to more general Volterra operators.

This is based on a joint work with Ilias Zadik.

Homotopy Theory

Speaker: Mike Misamore (Western)

"Applications of dg-categories"

Time: 14:30

Room: MC 107

Analysis Seminar

Speaker: Nadya Askaripour (University of Cincinnati )

"Spaces of automorphic functions and projections on these spaces"

Time: 11:30

Room: MC 108

This will be a survey talk. Let R be a Riemann surface, I will talk about some spaces of automorphic functions on R. Poincare series map is one way to construct automorphic forms, but it might not be convergent when we have an automorphic function. Some projections on automorphic functions will be introduced, also I will show few applications of these projections.

Index Theory Seminar

Speaker: Matthias Franz (Western)

"The infinitesimal index II"

Time: 12:00

Room: MC 107

This time we look at the cotangent bundle of a representation M of a torus. We discuss how the infinitesimal index gives an isomorphism between equivariant cohomology modules induced by the orbit filtration of M and certain spaces of splines which we are going to define.

Colloquium

Speaker: Uli Walther (Purdue)

"Local cohomology (of determinantal ideals)"

Time: 15:30

Room: MC 107

We give an introduction to the theory of local cohomology by pointing out examples and its connections to topology, differential equations, and algebraic geometry. We discuss, in the presence of a field, some techniques for investigating local cohomology modules, focussing on the study of finiteness conditions. We show how the absence of a field, or singularities in the ambient space, complicate things significantly, and work out the case of the variety consisting of matrices of bounded rank over every field and over the integers.