Seminari/Colloquia
Pagina 14
Date  Type  Start  End  Room  Speaker  From  Title 

06/10/23  Seminario  14:30  15:30  1201 Dal Passo  "Generalized YetterDrinfeld modules and the center construction of bimodule categories"
A YetterDrinfeld module (=YDmodule) over a bialgebra H is at the same time module and comodule over H satisfying a compatibility condition. It is wellknown that the category of YDmodules (over a finitedimensional Hopf algebra H) is equivalent to the center of the monoidal category of H(co)modules as well as the category of modules over Drinfeld doubles of H. Canaepeel, Militaru, and Zhu introduced generalized YDmodules. More precisely, they consider two bialgebras H, K, together with a bicomodule algebra C and bimodule coalgebra over them. A generalized YDmodule in their sense, is simultaneously an Amodule and a Ccomodule with a compatibility condition. Under a finiteness condition, they showed that these modules are exactly modules over a suitable constructed smash product build out of A and C. The aim of this talk is to show how the category of the generalized YDmodules can be obtained as
a relative center of the category Amodules, viewed as a bimodule category over categories of Hmodules and Kmodules. Moreover, we also show how other variations of YDmodules, such as antiYDmodules, arise as a particular case.
This talk is based on ongoing work with Joost Vercruysse.  
26/09/23  Seminario  16:00  17:00  1201 Dal Passo  Jonathan BenArtzi  Cardiff University (UK)  Quantifying the complexity of everyday computations: from abstract ideas to applications in spectral theory
In the first part of this talk I will present the Solvability Complexity Index — a theory developed with several coauthors over the last decade to help us classify the complexity of everyday computations. This theory serves as a bridge between classifications of degrees of complexity in theoretical computer science, and applications in numerical analysis. In the second part of the talk, I will discuss recent results where these ideas were applied to the computation of resonances, providing the first algorithms that work in any dimension.
Note: This talk is part of the activity of the MIUR Department of Excellence Project MatMod@TOV (20232027) 
19/09/23  Seminario  14:30  15:30  1201 Dal Passo  Alfio Borzì  Universität Würzburg  Stabilization of a kinetic model with collision by a feedbacklike control field in a Monte Carlo framework
The construction of feedbacklike control fields for kinetic models in phase space are discussed. The purpose of these controls is to drive an initial density of particles in the phase space to reach a desired cyclic trajectory on the phase space and follow it in a stable way. For this purpose, an ensemble optimal control problem governed by the kinetic model is formulated in a way that is amenable to a Monte Carlo approach.
The proposed formulation allows to define a oneshot solution procedure consisting in a backward solve of an augmented adjoint kinetic model.
Results of numerical experiments demonstrate the effectiveness of the proposed control strategy.

12/09/23  Seminario  14:30  15:30  1201 Dal Passo  Biagio Cassano  Università delle Campania “Luigi Vanvitelli  Sharp exponential decay at infinity for solutions to the perturbed Dirac equation
We determine the largest rate of exponential decay at infinity for nontrivial solutions to the stationary Dirac equation in presence of a (possibly nonHermitian) matrixvalued perturbation V such that V(x) goes as x^(e) at infinity, for infty < e < 1. Also, we show that our results are sharp for n=2,3, providing explicit examples of solutions that have the prescribed decay, in presence of a potential with the related behaviour at infinity. In this sense, our work is a result of unique continuation from infinity for the Dirac operator.
NB:This talk is part of the activity of the MIUR Excellence Department Project MATH@TOV CUP E83C23000330006 
14/07/23  Seminario  15:00  16:00  1201 Dal Passo  Timothy Rainone  Occidental College, Los Angeles, CA  The Matricial Field property in crosssectional C*algebras
Blackadar and Kirchberg introduced the notion of a Matricial Field (MF) C*algebra; an algebra is MF if it can be embedded into a corona of matrix algebras. We will discuss this property in crossedproducts arising from C*dynamical systems and more generally in crosssectional C*algebras constructed from Fell bundles. The C*analogue of Connes' embedding conjecture is the BlackadarKIrchberg Question (BKQ) which asks whether every stablyfinite algebra admits the MF property. Using Ktheoretic techniques we can answer this question in the affirmative for certain crossed products of classificable algebras by free groups.

10/07/23  Seminario  14:30  15:30  1201 Dal Passo  Juan J. Manfredi  University of Pittsburgh  Asymptotic mean value expansions for solutions of general elliptic and parabolic equations
The classical mean value property characterizes harmonic functions. It can be extended
to characterize solutions of many linear equations. We will focus in an asymptotic form of
the mean value property that characterizes solutions of nonlinear equations. This question
has been partially motivated by the connection between Random TugofWar games and the
normalized pLaplacian equation discovered some years ago, where a nonlinear asymptotic
mean value property for solutions of a PDE is related to a dynamic programming principle
for an appropriate stochastic game. Our goal is to show that an asymptotic nonlinear mean
value formula holds for several types of nonlinear elliptic equations.
Our approach is flexible and allows us to consider several families of operators obtained
as an infimum, a supremum, or a combination of both infimum and supremum, of linear
operators. We study both when the set of coefficients is bounded and unbounded (each
case requires different techniques). Examples include Pucci, Issacs, MongeAmpere, and
kHessian operators and some of their parabolic versions.
This talk is based in joint work with Pablo Blanc (Buenos Aires), Fernando Charro
(Detroit), and Julio Rossi (Buenos Aires).

04/07/23  Seminario  14:30  15:30  1201 Dal Passo  Gabriele Benomio  Princeton University (USA)  Nonlinear stability and instability in the analysis of the Einstein equations
The Einstein equations are the governing equations of general relativity and admit an initial value formulation as a system of nonlinear wave equations. The talk will present some stability and instability results for stationary (black hole) solutions to such evolution equations, enlightening interesting connections between the dynamics of solutions and the number of dimensions considered. No prior exposure to general relativity will be assumed.
Note: This talk is part of the activity of the MIUR Department of Excellence Project MatMod@TOV (20232027) 
27/06/23  Seminario  14:30  15:30  1201 Dal Passo  Wei Cheng  Nanjing University (China)  Propagation of singularities & minimizing movement
There are various notions of singular characteristics in the theory of propagation of singularities to viscosity solutions. In this talk, we will discuss a variational construction of generalized characteristics and strict singular characteristics. We proved the solution of generalized characteristics can be constructed in an intrinsic way using the idea of minimizing movements and certain process of homogenization. Moreover, the relation between the strict singular characteristics and the EDIEVI frame of gradient flow was also discussed. These results bridge various different topics such as Hamiltonian dynamical systems, weak KAM theory, cut locus in geometry, homogenization and gradient flow theory.
This talk is based on our latest work with Piermarco Cannarsa, Jiahui Hong and Kaizhi Wang. Note: This talk is part of the activity of the MIUR Department of Excellence Project MatMod@TOV (20232027) 
20/06/23  Seminario  14:30  15:30  1201 Dal Passo  Loredana Lanzani  Università di Bologna  Applications of the CalderònZygmund theory to holomorphic singular integrals
See the attached
pdf file
Note: This talk is part of the activity of the MIUR Department of Excellence Project MatMod@TOV (20232027) 
15/06/23  Seminario  16:00  17:00  1201 Dal Passo  Cecilia Gonzalez Tokman  University of Queensland  Quenched limit laws and thermodynamic formalism for random dynamical systems
Nonautonomous or random dynamical systems (RDS) provide useful and flexible models to investigate systems whose evolution depends on external factors, such as noise and seasonal forcing. Modern developments on multiplicative ergodic theory and transfer operators allow us to get useful insights into the longterm behavior of these systems. In this talk, we will present results in this direction, including (quenched) limit theorems and thermodynamic formalism for a class of RDS. Our results will be illustrated with examples, including random open and closed intermittent maps and nontransitive systems. This talk is based on collaborations with J. Atnip, D. Dragicevic, G. Froyland and S. Vaienti.

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