11th European Intensive Course on Complex Analysis  

and applications to partial differential equations

Departamento de Matemática, Universidade de Coimbra, Portugal

  May 23 to June 3, 2005

Goal of the Course

This intensive course follows the ten held at the Universities of Coimbra and Aveiro from 1995 to 2004 (1995, 1996, 1997, 1998, 1999, 2000, 2001, 2002, 2003, 2004) and there are plans for intensive courses in the following years. The lecture notes of some of the courses have been published in Coimbra and others are in print.

This intensive course will have a total of 40 hours of lectures and is at postgraduate level. Lecturers will have time available to discuss with the students. Successfully participating students will get a certificate. This course is organized by the Universities of Coimbra and Aveiro with the same goals as the ones organized under the Socrates/Erasmus Intensive Program of Higher Education, and is opened to all young mathematicians interested in Complex Analysis and its applications.

There will be a Workshop on "Applications and Generalizations of Complex Analysis" on the 4th of June 2005. 

First Week

 

May 23 (room 5.5)

May 24 (room 2.3)

May 25 (room 2.3)

May 26

May 27 (room 5.5)

Opening session

9h30m-10h

       
Gerhard Jank 

10h-12h30m

10h-12h30m

 

 

10h-12h30m

14h30m-17h

Francisco Marcellán

15h30m-18h

14h30m-17h

10h-12h30m

 

 

14h30m-17h

Second Week

 

May 30 (room 5.5)

May 30 (room 2.3)

June 01 (room 2.3)

June 02 (room 2.3)

June 03 (room 5.5)

Eric Lehman

10h-12h30m

10h-12h30m

 

10h-12h30m

10h-12h30m

Fred Brackx

14h30m-17h

14h30m-17h

10h-13h

 
Nele De Schepper    

14h30m-17h

14h30m-17h

 

Social Program    

 

 

14h30m-17h

Author: Francisco Marcellán Espańol, Universidad Carlos III de Madrid, Spain

first week

 Title: Orthogonal Polynomials on the unit circle. From Gabor Szegö to Barry Simon
 Summary: In the last ten years an increasing effort in  the theory of  orthogonal polynomials with respect to probability measures supported  on the unit circle has been done. The very recent monograph by Barry  Simon constitutes a good example of the fact how a well stated theory can be renewed using innovative tools and approaches coming from other  areas of mathematics as  well as from applications.
The aim of this set of lectures is to present the basic background in the theory stated by Gabor Szegö in the thirties and intensively  developed from an analytic point of view during the second half of the last century by Ya. Geronimus, P. Nevai, E. Rakhmanov among others.
 This overview will cover the following topics:
  1.- Orthogonal polynomials on the unit circle. Verblunsky coefficients. Carathéodory and Schur functions.
  2.- Szegö's Theorem.
  3.- Geronimus Theorem.
  4.- CGT and CMV representations. Spectral consequences.
  5.- Rakhmanov,s Theorem.
  References:
 
B. Simon, Orthogonal Polynomials on the unit circle, Part I: Classical Theory. Part II: Spectral Theory, Colloquium Applications, Volume 34, American Mathematical Society, Providence, Rhode Island, 2005.
 Author: Gerhard Jank, Aachen University, Germany.

first week

 Title: Matrix Differential Riccati Equations
 Summary: The interest in Riccati equations has become huge, especially in recent decades and the literature on the subject comprises thousands of items. Much of the research in Riccati equations is motivated by applications in mathematics, science and engineering. Specific ares of applications for instance are: Spectral factorization of operators, decoupling of systems of linear differential or difference equations, singular perturbation theory, boundary value problems for systems of ODE's, etc.. Applications in engineering or economics are in optimal control theory, dynamic game theory, robust control, just to mention a few.
From the standpoint of theoretical mathematics, Riccati equations represent a relatively well understood, albeit not without its own intricacies and subtleties, class of nonlinear equations. They can be linearized by a nonlinear transformation and exhibit several remarkable properties. As a consequence from the nonlinearity, solutions of differential Riccati equations show "blow ups", i.e. can have a finite escape time. One of the key issue regarding applications of Riccati equations is to find conditions that guarantee, depending on the parameters and initial data, existence of "global" solutions, i.e. that do not escape in finite time.
In the course many of these fundamental mathematical questions will be addressed. It is intended to present an overview of recent results on the representation of solutions, their asymptotic behaviour (phase portrait) and the finite escape time phenomenon. Depending on the time available, also some applications will be discussed.
Author: Eric Lehman,  Université de Caen, France

second week

 Title: Monogenic, hypermonogenic and holomorphic Cliffordian functions
 Summary: The Clifford algebras are generalizations of the field of complex numbers. The concept of holomorphic function of a complex variable may be extended to these realms in several ways. We will study three classes of functions generalizing the holomorphic functions: the monogenic functions, the hypermonogenic functions and the holomorphic Cliffordian functions. We will stress the the interrelation between these classes of functions in different dimensions. We end the course by some application, for instance we will build and study the Cliffordian elliptic functions, which is a nice shortcut to the ordinary elliptic functions.
Author: Fred Brackx, University of Ghent, Belgium

second week

 Title: Transform Analysis: The Hilbert Transform
 Summary: The first part of the course treats the Hilbert Transform, which is basic in the classical theory of the singular integral operators. The Hilbert Transform is at the crosspoint of real and complex analysis and fundamental to the study of boundary values of Cauchy transforms of L2-functions on the real line, the unit circle, half-space and the unit sphere. It leads to the study of Hardy spaces of harmonic, holomorphic and monogenic functions. The Hilbert Transform is used in the theoretical description of electronic devices and systems, and the elements of the Hardy space, the so-called analytic signals, are fundamental to the theories of signals, circuits and systems.
The concept of Hilbert transform is first introduced in the complex plane (on the real line and on the boundary of bounded regions), but the course especially focusses on the study of the Hilbert transform in Euclidean space, in the framework of Clifford analysis.
Author: Nele De Schepper, University of Ghent, Belgium

second week

 Title: Transform Analysis: The Continuous Wavelet Transform
 Summary: The second part of the course treats the Continuous Wavelet Transform [CWT]. The CWT belongs, such as the Windowed Fourier Transform or Gabor Transform, to the class of time-frequency representations of signals. These representations are, contrary to the classical Fourier Transform, particularly suited for the analysis of non-stationary, inhomogeneous signals. Many applications amply demonstrate that the CWT is a successful tool for the analysis of signals and feature detection in signals.
First the concept of the CWT is introduced on the real line and in Euclidean space. Then a unifying construction of multi-dimensional wavelets, in the framework of Clifford analysis, is presented. Starting point for this construction of Clifford-wavelets, is the introduction of new polynomials in Euclidean space, generalizing classical orthogonal polynomials. A selection procedure leads to specific Clifford mother wavelets such as the Clifford-Hermite, the Clifford-Gegenbauer and the Clifford-Laguerre wavelets.

Living expenses can be partially covered for some students if they do not have support from their own institution and if there is enough money available.

Anabela Monteiro Paiva, Universidade da Beira Interior, Portugal
Hennie De Schepper, University of Ghent, Belgium
Gil Bernardes, Universidade de Coimbra, Portugal
Jarkko Kettunen, Tampere University of Technology, Finland 
José Carlos Soares Petronilho, Universidade de Coimbra, Portugal.
Joana Soares, Universidade do Minho, Portugal
Luis Manuel da Silva Cotrim, Instituto Politécnico de Leiria, Portugal
Maria Francisca Matos Cabo, Universidade de Coimbra, Portugal
Maria das Neves Vieiro Rebocho, Universidade da Beira Interior, Portugal
Milton Ferreira, Universidade de Aveiro, Portugal.
Nelson Faustino, Universidade de Aveiro, Portugal.
Nelson Vieira, Universidade de Aveiro, Portugal.
Roberto Costas Santos, Universidad Carlos III de Madrid, Spain
Sandra Orfăo, Aachen University, Germany.
Amílcar Branquinho (Departamento de Matemática Universidade de Coimbra)
Helmuth Malonek (Departamento de Matemática da Universidade de Aveiro)
Jaime Carvalho e Silva (Departamento de Matemática Universidade de Coimbra)
Paula Cerejeiras (Departamento de Matemática da Universidade de Aveiro)
With support from CMUC (Centro de Matemática da Universidade de Coimbra), UI&D "Matemática e Aplicaçőes" da Universidade de Aveiro, and the Socrates programme