13/12/18  Colloquium  14:30  15:30  1201 Dal Passo  Fulvio RICCI  SNS  Pisa  Aspetti dell'analisi sferica su spazi omogenei commutativi a crescita polinomiale
Uno spazio omogeneo M = G/K connesso di un gruppo di Lie G, con K sottogruppo compatto, si dice commutativo  si dice anche che (G,K) è una coppia di Gelfand  se l’algebra degli operatori differenziali Ginvarianti su M è commutativa.
Nell’analisi di funzioni e di operatori Ginvarianti su M, la trasformata sferica ha un ruolo analogo a quello svolto dalla trasformata di Fourier quando M = G = R^{n}.
Le analogie tra trasformata sferica e trasformata di Fourier classica diventano più forti utilizzando la rappresentazione, dovuta a F. Ferrari Ruffino, dello spettro di Gelfand come sottoinsieme chiuso di uno spazio euclideo.
In questo seminario presentiamo risultati recenti e problemi aperti sulla caratterizzazione delle trasformate sferiche di funzioni di Schwartz su M quando G ha crescita polinomiale. 
12/12/18  Seminario  17:30  18:30  1201 Dal Passo  Kei Hasegawa  University of Kyoto  BassSerre trees for amalgamated free products of C*algebras and applications
The BassSerre tree associated to an amalgamated free product of groups is a tree on which the group acts in a canonical way. This action is a powerful tool in various studies of the group itself.
In this talk, I will introduce its analogy for amalgamated free products of C*algebras, and explain how ideas coming from geometric group theory can be used in the C*algebra setting. 
12/12/18  Seminario  16:00  17:00  1201 Dal Passo  Yusuke Isono  RIMS Kyoto  Intertwining theory for general von Neumann algebras and applications
We investigate Popa's intertwining condition, using TomitaTakesaki's modular theory. In particular, we give a new characterization of Popa's condition in terms of their continuous cores.
In this talk, I will explain the idea and the difficulty of proving this
characterization, and also mention some applications.

11/12/18  Seminario  14:30  15:30  1201 Dal Passo  Sunra Mosconi  Universita' di Catania  The ShrodingerPoisson system with sign changing potential
The ShrodingerPoisson system describes the motion of an electrically charged BoseEinstein condensate subjected to potential field. We will consider the problem of existence of standing waves of arbitrary high energy. By solving the Poisson equation, this results in studying a stationary nonlinear Shrodinger equation with a nonlocal signchanging potential. Standard variational method apply when considering suitable nonlinearities, but fail for the simple yet paramount case of the GrossPitaevski equation. We will describe the physical model, discuss the variational formulation and related literature and propose a solution in the GrossPitaevski setting. This is a joint work with S. Liu, University of Xiamen 
10/12/18  Seminario  14:30  15:30  1201 Dal Passo  Gwyn BELLAMY  Glasgow University 
Resolutions of symplectic quotient singularities
In this talk I will explain how one can explicitly construct all crepant resolutions of the symplectic quotient singularities associated to wreath product groups. The resolutions are all given by Nakajima quiver varieties. In order to prove that all resolutions are obtained this way, one needs to describe what happens to the geometry as one crosses the walls inside the GIT parameter space for these quiver varieties. This is based on joint work with Alistair Craw.
N.B.: this talk is part of the activity of the MIUR Excellence Department Project CUP E83C18000100006 
04/12/18  Seminario  14:30  15:30  1201 Dal Passo  Benedetta Pellacci  Universita' della Campania  Asymptotic spherical shapes in some spectral optimization problems
We study the positive principal eigenvalue of a weighted problem associated with the Neumann Laplacian. This analysis is related to the investigation of the survival threshold in population dynamics. When trying to minimize such eigenvalue with respect to the weight, one is lead to consider a shape optimization problem, which is known to admit spherical optimal shapes only in very specific cases. We investigate whether spherical shapes can be recovered in general situations, in some singular perturbation limit. We also consider a related problem, where the diffusion is triggered by a fractional
$s$Laplacian, and the optimization is performed with respect to the fractional order $sin(0,1]$. These are joint works with Dario Mazzoleni and Gianmaria Verzini. 
03/12/18  Seminario  14:30  15:30  1201 Dal Passo  Spela SPENKO  Vrije Universiteit Brussel  Comparing commutative and noncommutative resolutions of singularities
Quotient singularities for reductive groups admit the canonical Kirwan (partial) resolution of singularities, and often also a noncommutative resolution. We will motivate the occurrence of noncommutative resolutions and compare them to their commutative counterparts (via derived categories in terms of the BondalOrlov conjecture). This is a joint work with Michel Van den Bergh. 
20/11/18  Colloquium  14:30  16:30  1201 Dal Passo  Masayasu Mimura  Musashino University/Meiji University  Transient SelfOrganization: Closed Systems vs. Open systems of Reaction and Diffusion
After Turing?s theoretical prediction on biological pattern formation, various types of patterns related to selforganization can be discovered in open systems due to the interaction of reaction with
diffusion. Turing said in his paper ?The model will be a simplification and an idealization, and consequently a falsification. It is to be hoped that the features retained for discussion are those of
greatest importance in the present state of knowledge?. Nevertheless, mathematical communities have been much influenced by his theory. We already recognize that open systems of reaction and diffusion have
generated enormous rich behaviors. On the other hand, closed systems have been gradually less interesting. However, I would like to emphasize that new biological pattern formation can be observed even in
closed systems as the consequence of transient selforganization, and that the theoretical understanding of such patterns is a very important subject in nonlinear mathematics. 
16/11/18  Seminario  17:15  18:15  1201 Dal Passo  Peter LITTELMANN  Cologne University  Standard Monomial Theory via NewtonOkounkov Theory
Sequences of Schubert varieties, contained in each other and successively of codimension one, naturally lead to valuations on the field of rational functions of the flag variety. By taking the minimum over all these valuations, one gets a quasi valuation which leads to a flat semitoric degeneration of the flag variety. This semitoric degeneration is strongly related to the Standard Monomial Theory on flag varieties as originally initiated by Seshadri, Lakshmibai and Musili. This is work in progress jointly with Rocco Chirivi and Xin Fang. 
16/11/18  Seminario  15:45  16:45  1201 Dal Passo  Michèle VERGNE  Institut de Mathématiques de Jussieu / Académie de Sciences  Paris  Quiver Grassmannians, Qintersection and Horn conditions
The abstract is available here. 