ALBERTO BRESSAN, Pennsylvania State University
NON-COOPERATIVE DIFFERENTIAL GAMES
Giovedì 25 Febbraio 2010, ore 11:30
Dipartimento di Matematica, Politecnico di Milano, Sala Consiglio VII piano | |
|
|
| |
TIM STEGER, Università di Sassari
50 FAKE PLANES
Lunedì 15 Febbraio 2010, ore 15:00
Aula seminari 3014, Dipartimento di Matematica, Università di Milano Bicocca | |
|
|
| |
Renzo Ricca, Università di Milano-Bicocca
On Gauss' linking number and the energy spectrum of magnetic knots
Mercoledì 16 Dicembre 2009, ore 17:00
Dipartimento di Matematica, Università di Milano, Via Saldini | |
|
|
| |
Giorgio Fusco, Università dell Aquila
Equivariant entire solutions to elliptic
systems with variational structure
Giovedì 19 Novembre 2009, ore 15:00
Università di Milano Bicocca, Dipartimento di Matematica e Applicazioni, aula 3014 edificio U5 III piano | |
|
|
| |
Bernard Helffer, Université de Paris XI
On Nodal domains and spectral minimal partitions: new results and open problems
Lunedì 26 Ottobre 2009, ore 17:00
Università di Milano-Bicocca, Dipartimento di Matematica e Applicazioni, aula 45 II piano |
|
|
Abstract
|
 |
 |
Given a bounded open set $\Omega$
in $\mathbb{R}^2$ or in a Riemannain manifold
and a partition of $\Omega$
by $k$ open sets $\omega_j$ , we can consider the quantity
$\max_j \lambda(\omega_j)$ where $\lambda(\omega_j)$ is the ground state energy of
the Dirichlet realization of the Laplacian in $\omega_j$. If we denote by
$\mathcal{L}_k(\Omega
)$ the infimum over all the $k$-partitions of
$\max_j \lambda(\omega_j)$, a minimal $k$-partition is then a partition which
realizes the infimum.
Although the analysis is rather standard when $k=2$ (we find the nodal domains of a second
eigenfunction), the analysis of higher $k$ becomes non trivial and quite interesting.
In this talk, we would like to discuss the properties of minimal spectral partitions,
illustrate the difficulties by considering simple cases like the disc, the rectangle
or the sphere ($k = 3$) and also exhibit the possible role of the hexagone in the
asymptotic behavior as $k \to \infty$ of
$\mathcal{L}_k(\Omega
)$. We will also explain the link of these questions with spectral
properties of some Aharonov-Bohm hamiltonians.
We will finally discuss other definitions of minimal partitions.
This work has started in collaboration with T. Hoffmann-Ostenhof and has been continued
(published or to appear) with the coauthors V. Bonnaillie-Noel, T. Hoffmann-Ostenhof, S. Terracini
and G. Vial. |
|
|
| |
Wei-Min Wang, Université Paris-Sud
Spectral method in Hamiltonian PDE
Lunedì 12 Ottobre 2009, ore 17:30
Dipartimento di Matematica, Universita di Milano | |
|
|
| |
|
|
|
|
