17/06/24  Seminario  15:00  16:00  1201 Dal Passo  Tan BuiThanh  University of Texas at Austin  Learn2Solve: A Deep Learning Framework for RealTime Solutions of Forward, Inverse, and UQ Problems
Digital models (DMs) are designed to be replicas of systems and processes. At the core of a digital model (DM) is a physical/mathematical model that captures the behavior of the real system across temporal and spatial scales. One of the key roles of DMs is enabling “what if” scenario testing of hypothetical simulations to understand the implications at any point throughout the life cycle of the process, to monitor the process, to calibrate parameters to match the actual process and to quantify the uncertainties. In this talk, we will present various (faster than) realtime Scientific Deep Learning (SciDL) approaches for forward, inverse, and UQ problems. Both theoretical and numerical results for various problems including transport, heat, Burgers, (transonic and supersonic) Euler, and NavierStokes equations will be presented. 
07/06/24  Seminario  14:30  15:30  1201 Dal Passo  Paolo ASCHIERI  Università del Piemonte Orientale 
Algebra & Representation Theory Seminar (ARTS)
"Bundles on quantum projective varieties and their differential geometry"
N.B.: this talk is part of the activity of the MIUR Excellence Department Project MatMod@TOV (CUP E83C23000330006)
We study quantum principal bundles on projective varieties using a sheaf theoretic approach. Differential calculi are introduced in this context. The main class of examples is given by covariant calculi over quantum flag manifolds, which we provide via an explicit Ore extension construction. We next introduce principal covariant calculi by requiring a local compatibility of the calculi on the total sheaf, base sheaf and the structure Hopf algebra in terms of exact sequences. The examples of principal (covariant) calculi on the quantum principal bundles SL_{q}(2,C) and GL_{q}(2,C) over the projective space P^{1}(C) are presented. 
06/06/24  Seminario  14:30  15:30  1201 Dal Passo  John Pearson  University of Edinburgh  Recent Developments in the Numerical Solution of PDEConstrained Optimization Problems
Optimization problems subject to PDE constraints form a mathematical tool that can be applied to a wide range of scientific processes, including fluid flow control, medical imaging, option pricing, biological and chemical processes, and electromagnetic inverse problems, to name a few. These problems involve minimizing some function arising from a particular physical objective, while at the same time obeying a system of PDEs which describe the process. It is necessary to obtain accurate solutions to such problems within a reasonable CPU time, in particular for timedependent problems, for which the “allatonce” solution can lead to extremely large linear systems.
In this talk we consider iterative methods, in particular Krylov subspace methods, to solve such systems, accelerated by fast and robust preconditioning strategies. In particular, we will survey several new developments, including block preconditioners for fluid flow control problems, a circulant preconditioning framework for solving certain optimization problems constrained by fractional differential equations, and multiple saddlepoint preconditioners for block tridiagonal linear systems. We will illustrate the benefit of using these new approaches through a range of numerical experiments.
This talk is based on work with Santolo Leveque (Scuola Normale Superiore, Pisa), Spyros Pougkakiotis (Yale University), Jacek Gondzio (University of Edinburgh), and Andreas Potschka (TU Clausthal).
This talk is part of the activity of the MUR Excellence Department Project MatMod@TOV (CUP E83C23000330006). 
06/06/24  Seminario  14:00  15:00  1101 D'Antoni  Lei Zhang  University of Florida  Seminario di Equazioni Differenziali
(Nota: Cambio di giorno, orario e aula)
Asymptotic Analysis and Uniqueness of blowup solutions of nonquantized singular mean field equations
For singular mean field equations defined on a compact Riemann surface, we prove the uniqueness of bubbling solutions when blowup points are either regular points or nonquantized singular sources. In particular the uniqueness result covers the most general case extending or improving all previous works. For example, unlike previous results, we drop the assumption of singular sources being critical points of a suitably defined KirchoffRouth type functional. Our argument is based on refined estimates, robust and flexible enough to be applied to a wide range of problems requiring a delicate blowup analysis. In particular we come up with a major simplification of previous uniqueness proofs. This is a joint work with Daniele Bartolucci and Wen Yang.
Note:
This talk is part of the activity of the MIUR Department of Excellence Project MatMod@TOV (20232027)

04/06/24  Colloquium  14:30  15:30  1201 Dal Passo  Martin HAIRER  EPFL Lausanne & Imperial College, London  Colloquium Levi Civita (CMTP)
“Supercritical KPZ equations”
Like many discrete statistical mechanics models, stochastic PDEs can exhibit a “critical dimension” beyond which their largescale behaviour is expected to be trivial (i.e. governed by Gaussian fluctuations). While such sweeping heuristics allow us to formulate rather precise conjectures, there are relatively few cases where these have actually been proven. In this talk, we will mainly focus on the KPZ equation, a standard model of interface fluctuations. There has recently been substantial progress in our mathematical understanding of its largescale behaviour in the supercritical regime. 
29/05/24  Seminario  17:30  18:30  1201 Dal Passo  Claudio Dappiaggi  Università di Pavia 
Operator Algebras Seminar
On the stochastic SineGordon model: an AQFT perspective
We investigate the massive SineGordon model in the finite ultraviolet regime on the twodimensional Minkowski spacetime with an additive Gaussian white noise. In particular we construct the expectation value and the correlation functions of a solution of the underlying stochastic partial differential equation (SPDE) as a power series in the coupling constant, proving ultimately uniform convergence. This result is obtained combining an approach to study SPDEs at a perturbative level which a recent analysis of the quantum sineGordon model using techniques proper of the perturbative, algebraic approach to quantum field theory (pAQFT). This is a joint work with A. Bonicelli and P. Rinaldi, https://arxiv.org/pdf/2311.01558
Note: This talk is part of the activity of the MUR Excellence Department Project MatMod@TOV (CUP E83C23000330006)
The Operator Algebra Seminar schedule is here: https://sites.google.com/view/oastorvergata/homepage?authuser=0

29/05/24  Seminario  16:00  17:00  1201 Dal Passo  Stefaan Vaes  KU Leuven 
Operator Algebras Seminar
Ergodic states on type III_1 factors and ergodic actions
I will report on a joint work with Amine Marrakchi. Since the early days of TomitaTakesaki theory, it is known that a von Neumann algebra that admits a state with trivial centralizer must be a type III_1 factor, but the converse remained open. I will present a solution of this problem, proving that such ergodic states form a dense G_delta set among all normal states on any III_1 factor with separable predual. Through Connes' RadonNikodym cocycle theorem, this problem is related to the existence of ergodic cocycle perturbations for outer group actions, which I will discuss in the second half of the talk.
Note: This talk is part of the activity of the MUR Excellence Department Project MatMod@TOV (CUP E83C23000330006) 
28/05/24  Seminario  14:30  16:00  1101 D'Antoni  Karl Christ  UT Austin  Geometry Seminar Irreducibility of Severi varieties on toric surfaces
Severi varieties parametrize integral curves of fixed geometric genus in a given linear system on a surface. In this talk, I will discuss the classical question of whether Severi varieties are irreducible and its relation to the irreducibility of other moduli
spaces of curves. I will indicate how tropical methods can be used to answer such irreducibility questions. The new results are from ongoing joint work with Xiang He and Ilya Tyomkin.
Note:
This talk is part of the activity of the MIUR Department of Excellence Project MatMod@TOV (20232027) 
24/05/24  Seminario  16:00  17:00  1101 D'Antoni  Ulrich KRÄHMER  TU Dresden 
Algebra & Representation Theory Seminar (ARTS)
(N.B.: mind the change of room!)
The ring of differential operators
on a monomial curve is a Hopf
algebroid
N.B.: this talk is part of the activity of the MIUR Excellence Department Project MatMod@TOV (CUP E83C23000330006)
The ring of differential
operators on a cuspidal curve
whose coordinate ring is a numerical
semigroup algebra
is shown to be a
cocommutative and cocomplete
left Hopf algebroid. If the
semigroup is symmetric so that the
curve is Gorenstein, it is a full
Hopf algebroid (admits an antipode).
Based on joint work with Myriam
Mahaman. 
24/05/24  Seminario  14:30  15:30  1101 D'Antoni  Giovanni PAOLINI  Università di Bologna 
Algebra & Representation Theory Seminar (ARTS)
joint session with
Topology Seminar
(( N.B.: mind the change of room! ))
"Dual Coxeter groups of rank three"
N.B.: this talk is part of the activity of the MIUR Excellence Department Project MatMod@TOV (CUP E83C23000330006)
In this presentation, I will discuss the combinatorics of the noncrossing partition posets associated with Coxeter groups of rank three. In particular, I will describe the techniques used to prove the lattice property and lexicographic shellability. These properties can then be used to solve several problems on the corresponding Artin groups, such as the K(π,1) conjecture, the word problem, the center problem, and the isomorphism between standard and dual Artin groups.
This is joint work with Emanuele Delucchi and Mario Salvetti. 