16/11/18  Seminario  14:30  15:30  1201 Dal Passo  Michel BRION  Université de Grenoble  Automorphisms of almost homogeneous varieties
The automorphism group of a projective variety X is known to be a “locally algebraic group”, extension of a discrete group (the group of components) by a connected algebraic group. But the group of components of Aut(X) is quite mysterious; in particular, it is not necessarily finitely generated. In this talk, we will discuss the structure of Aut(X) when X has an action of an algebraic group with an open dense orbit.
In particular, we will see that the group of components is arithmetic (and hence finitely generated) under this assumption. 
06/11/18  Seminario  16:00  17:00  1101 D'Antoni  Tatsuo Suwa  Hokkaido University  Relative Dolbeault cohomology and its application to the Sato hyperfunction
theory
The Cechde Rham cohomology together with its integration theory has been
effectively used in various problems related to localization of
characteristic classes. Likewise we may develop the CechDolbeault
cohomology theory and on the way we naturally come up with the relative
Dolbeault cohomology.
This cohomology turns out to be canonically isomorphic with the local
(relative) cohomology of A. Grothendieck and M. Sato so that it provides
a handy way of representing the latter.
In this talk we present the theory of relative Dolbeault cohomology and
give, as applications, simple explicit expressions of Sato
hyperfunctions, some fundamental operations on them and related local
duality theorems. Particularly noteworthy is that the integration of
hyperfunctions in our framework, which is a descendant of the integration
theory on the Cechde Rham cohomology, is simply given as the usual
integration of Stokes type. Also the Thom class in relative de Rham
cohomology plays an essential role in the scene of interaction between
topology and analysis.
The talk includes a joint work with N. Honda and T. Izawa. 
05/11/18  Seminario  16:00  17:00  1201 Dal Passo  Niels KOWALZIG  "Sapienza" Università di Roma  Higher brackets on cyclic and negative cyclic (co)homology
In this talk, we will embed the string topology bracket developed by ChasSullivan and Menichi on negative cyclic cohomology groups as well as the dual bracket found by de Thanhoffer de VoelcseyVan den Bergh on negative cyclic homology groups into the global picture of a noncommutative differential (or Cartan) calculus up to homotopy on the (co)cyclic bicomplex in general, in case a certain Poincar´ duality is given. For negative cyclic cohomology, this in particular leads to a BatalinVilkovisky algebra structure on the underlying Hochschild cohomology. In the special case in which this BV bracket vanishes, one obtains an e_3algebra structure on Hochschild cohomology. The results are given in the general and unifying setting of (opposite) cyclic modules over (cyclic) operads.
All this is joint work with D. Fiorenza. 
05/11/18  Seminario  14:30  15:30  1201 Dal Passo  Paolo BRAVI  "Sapienza" Università di Roma  Spherical functions and orthogonal polynomials
I will explain how some questions we asked a few years ago on the multiplication of spherical functions on symmetric spaces are related to the socalled linearization problem for a certain kind of orthogonal polynomials, namely Jacobi polynomials. I will state some conjectures in the particular case of Jack polynomials. 
31/10/18  Seminario  16:00  17:00  1201 Dal Passo  Maria Stella Adamo  Università di Catania  The problem of continuity for representable functionals on Banach quasi
*algebras.
A way to study problems concerning Quantum Statistical Mechanics is to
consider locally convex quasi ?algebras, for which Banach quasi
?algebras constitute a special class. For example, Banach quasi
?algebras can be obtained by taking the completion of a ?algebra A_0
with respect to a norm for which the multiplication is (only) separately
continuous.
In the (locally convex) quasi *algebras setting, a relevant role is
played by representable functionals. Roughly speaking a linear
functional will be called representable if it allows a GNSlike
construction.
In this talk, we discuss about the problem of continuity for these
functionals and some related results. We begin our discussion by looking
at the the properties of representable (and continuous) functionals,
especially in the simplest case of Hilbert quasi *algebras. This
discussion leads naturally to look at the problem of continuity for
these functionals, because no example of representable discontinuous
functional is known until now. Hence, we examine the approaches to study
this problem and the results about it. If the time permits, we will
discuss about future directions and applications. Joint work with C. Trapani 
30/10/18  Seminario  16:00  17:00  1101 D'Antoni  Uros Kuzman  University of Ljubljana  On Poletsky theory of discs in compact (almost) complex manifolds
We provide a direct construction of Poletsky discs via local
arc approximation and a Rungetype theorem. That is, we will discuss
approximation of nonholomorphic maps in almost complex manifolds and a
certain Okatype result by A. Gournay. 
24/10/18  Seminario  14:30  15:30  1201 Dal Passo  Mikhail Zaidenberg  Institut Fourier, Grenoble (France)  FanoMukai fourfolds of genus 10 and their automorphism groups (Algebraic Geometry Seminar, in the framework of Research Project "Families of curves: their moduli and their related varieties"  Mission Suistanability Tor Vergata, CUP: E8118000100005, Principal Investigator Flaminio Flamini)
The celebrated Hirzebruch Problem asks to describe all possible smooth compactifications of C^n with second Betti number 1. Projective completions of C^n $ are Fano varieties; in dimension at most 3 they are all known (Remmertvan de Ven, BrentonMorrow, Peternell, Prokhorov, Furushima). It occurs that any variety in the title provides a new example in dimension 4. These varieties form a 1parameter family. The group Aut^0(V) of a general member V of this family is isomorphic to the algebraic 2torus (C^*)^2. There are two exceptional members of the family with ${
m Aut}^0(V)$ equal GL(2, C} and C x C^*, respectively. The discrete part of the automorphism group Aut(V) is a finite cyclic group. To compute Aut(V) we use three different geometric realizations of Aut(V). The talk is based on a joint work with Yuri Prokhorov
[Algebraic Geometry Seminar, in the framework of Research Project "Families of curves: their moduli and their related varieties"  Mission Suistanability Tor Vergata, CUP: E8118000100005, Principal Investigator Flaminio Flamini] 
22/10/18  Seminario  16:00  17:00  1201 Dal Passo  Layla SORKATTI  AlNeelain University, Khartoum  Symplectic alternating algebras
We first give some general overview of symplectic alternating algebras and then focus in particular on the structure and classification of nilpotent symplectic alternating algebras.
N.B.: this talk is part of the activity of the MIUR Excellence Department Project CUP E83C18000100006 
10/10/18  Seminario  16:00  17:00  1201 Dal Passo  Alexander Stottmeister  Roma "Tor Vergata"  Operator algebras, lattice gauge theory, and renormalization
We will discuss an operatoralgebraic approach to lattice gauge theory and its relation to a recent construction by Jones of representations of the Thompson group. Furthermore, we will outline a framework of rigorous renormalization group theory and scaling/continuum limits in this context.

02/10/18  Seminario  14:30  15:30  1201 Dal Passo  Antonio Marigonda  Universita' di Verona  A Bolza problem for multiagent systems
A multiagent system is a system in the finitedimensional Euclidean space where the number of possibly interacting agents is so large that only a statistical description of the state of the system is actually available. A common way to model such kind of systems is to describe the state of the system at time t by mean of a Borel measure m_t where, for each Borel subset A of R^d, the quotient m_t(A)/m_t(R^d) represents the fraction of the total number of agents that are present in the set A at time t over the total number of agents. In the case where neither creation nor destruction of agents are allowed, we normalize the total mass to the constant 1, thus m_t becomes a timedepending probability measure. We consider such a system subject to a centralized controller aiming to minimize a cost function of Bolza type. We formulate the minimization problem as a problem for a dynamics in the Wasserstein space represented by a controlled continuity equation describing the macroscopical evolution of the system. We prove that the value function V of the problem solves a HamiltonJacobi equation in the Wasserstein space in a suitable viscosity sense, and prove a comparison principle for such an equation, thus characterizing V as the unique viscosity solution of the HamiltonJacobi equation associated to the problem. 