Periodic solutions of parabolic problems with discontinuous hysteresis

Speaker: 

Sergey Tikhomirov

Institution: 

Institute for Mathematics, Free University of Berlin

Time: 

Tuesday, November 1, 2011 - 2:00pm

Location: 

RH 440R

We consider the heat equation in a multidimensional domain with nonlocal hysteresis feedback control in a boundary condition. Thermostat is our prototype model.

By reducing the problem to a discontinuous infinite dynamical system, we construct all periodic solutions with exactly two switchings on the period and study their stability. In the problem under consideration, the hysteresis gap (the difference between the switching temperatures) is of especial importance.

If the hysteresis gap is large enough, then the constructed periodic solution is in fact unique and globally stable. For small values of hysteresis gap coexistence of several periodic solutions with different stability properties is proved to be possible.

This is a joint work with Pavel Gurevich.

Periodic solutions of parabolic problems with discontinuous hysteresis

Speaker: 

Sergey Tikhomirov

Institution: 

Institute for Mathematics, Free University of Berlin

Location: 

RH 440R

We consider the heat equation in a multidimensional domain with nonlocal hysteresis feedback control in a boundary condition.
Thermostat is our prototype model.

By reducing the problem to a discontinuous infinite dynamical system, we construct all periodic solutions with exactly two switchings on the period and study their stability. In the problem under consideration, the hysteresis gap (the difference between the switching temperatures) is of especial importance.

If the hysteresis gap is large enough, then the constructed periodic solution is in fact unique and globally stable. For small values of hysteresis gap coexistence of several periodic solutions with different stability properties is proved to be possible.

Continuous nonassociative cohomology

Speaker: 

Professor Bernard Russo

Institution: 

UCI

Time: 

Tuesday, October 18, 2011 - 3:00pm

Location: 

RH 306

I shall present known results on the following topics in the contexts of associative, Lie, and Jordan algebras:

1. Derivations and cohomology of finite dimensional algebras

2. Structure and continuity of derivations on operator and Banach algebras

3. Continuous cohomology of operator algebras, including perturbation theory and the role of complete boundedness

My purpose is to provide the background for a study of cohomology of Banach triple systems (associative, Lie, and Jordan), which currently exists only in finite dimensions, and minimally at that.

Reduction of Pfaffian systems and conservation laws

Speaker: 

Professor Chong-Kyu Ham

Institution: 

Seoul National University, Korea

Time: 

Tuesday, November 29, 2011 - 3:00pm

Location: 

RH 306

Given a Pfaan system on a smooth manifold, we shall discuss the
notion of reduced submanifold and how to nd them. This was motivated
from the problem of deciding the minimality of generic CR manifolds. As
best known by the Noether's theorem conservation laws arise from the
symmetry of dierential equations. We approach the conservation laws
from the viewpoint of the reduction of Pfaan systems and discuss some
possible applications.

The Cauchy Integral in $\mathbb C^n$

Speaker: 

Professor Loredana Lanzani

Institution: 

University of Arkansas

Time: 

Tuesday, January 10, 2012 - 3:00pm

Location: 

RH 306

The classical Cauchy integral is a fundamental object of complex analysis whose analytic properties are intimately related to the geometric properties of its supporting curve.

In this talk I will begin by reviewing the most relevant features of the classical Cauchy integral. I will then move on to the (surprisingly more involved) construction of the Cauchy integral for a hypersurface in
$\mathbb C^n$.

I will conclude by presenting new results joint with E. M. Stein concerning the regularity properties of this integral and their relations with the geometry of the hypersurface.

(Time permitting) I will discuss applications of these results to the Szeg\H o and Bergman projections (that is, the orthogonal projections of the Lebesgue space $L^2$ onto, respectively, the Hardy and Bergman spaces of holomorphic functions).

On relation between measures of maximal entropy of hyperbolic maps and the density of states of Fibonacci Hamiltonian

Speaker: 

Anton Gorodetski

Institution: 

UC Irvine

Time: 

Friday, October 28, 2011 - 2:00pm

Location: 

RH 440R

We consider the density of states measure of the Fibonacci Hamiltonian and show that, for small values of the coupling constant, this measure is exact-dimensional and the almost everywhere the local scaling exponent is a smooth function of the parameter, is strictly smaller than the Hausdorff dimension of the spectrum, and converges to one as the coupling constant tends to zero. The proof relies on a new connection between the density of states measure of the Fibonacci Hamiltonian and the measure of maximal entropy for the Fibonacci trace map on the non-wandering set in the invariant surface (level surface of the Fricke-Vogt invariant). This allows us to make a connection between the spectral problem at hand and the dimension theory of dynamical systems.
This is a joint work with David Damanik.

Pages

Subscribe to UCI Mathematics RSS