Bollettino settimanale
Settimana 14/11/2022 - 18/11/2022
Seminari
Università degli Studi Roma Tor Vergata
Dipartimento di Matematica
Geometry Seminar
Date: 15 November 2022
Schedule: 14:30 Rome Time
Where: Conference Room 1201 "Roberta Dal Passo"
Speaker: Alex Massarenti (Università di Ferrara)
Title: " On the unirationality of quadric bundles "
Abstract: A variety X over a field is unirational if there is a dominant rational map from a projective space to X.
We will prove that a general quadric bundle, over a number field, with anti-canonical divisor of positive volume and discriminant of odd degree is unirational,
and that the same holds for quadric bundles over an arbitrary infinite field provided that they have a point and that their dimension is at most five.
As a consequence we will get the unirationality of any smooth 4-fold quadric bundle over the projective plane, over an algebraically closed field, and with discriminant of degree at most 12.
Organizing Committee:
Codogni Giulio (Contact Mail)
Lido Guido Maria ( Contact Mail)
Onorati Claudio ( Contact Mail)
Further Information: Click here for geometry webpage
NOTE: For more information contact: Onorati Claudio Click here for mail
Streaming Link (MS Teams): This seminar will be held in person
Università degli Studi di Roma "Tor Vergata"
Dipartimento di Matematica
RoMaDS - Rome Center on Mathematics for Modeling and Data ScienceS
Date: 16 November 2022
Schedule: 14:00 Rome Time
Where: Conference Room Roberta Dal Passo
Speaker: Cesare Molinari (I.I.T. and Università di Genova)
Title: " Iterative regularization for convex regularizers "
Abstract/Program:
Iterative regularization exploits the implicit bias of an optimization algorithm to regularize ill-posed problems.
Constructing algorithms with such built-in regularization mechanisms is a classic challenge in inverse problems but
also in modern machine learning, where it provides both a new perspective on algorithms analysis, and significant
speed-ups compared to explicit regularization. In this talk, we propose and study the first iterative regularization
procedure able to handle biases described by non smooth and non strongly convex functionals, prominent in low-complexity
regularization. Our approach is based on a primal-dual algorithm of which we analyze convergence and stability properties,
even in the case where the original problem is unfeasible. The general results are illustrated considering the special case
of sparse recovery with the ℓ1 penalty. Our theoretical results are complemented by experiments showing the computational
benefits of our approach.
The seminar is part of the Excellence Project Math@TOV.
Organizing Committee:
Domenico Marinucci (Coordinator)
Filippo Bracci
Piermarco Cannarsa
Lucia Caramellino
Andrea Clementi
Giorgio Gambosi
Carla Manni
Michele Salvi
Benedetto Scoppola
Alfonso Sorrentino
Hendrik Speleers
Stefano Vigogna
Nicola Vittorio
Further Information: You can find a schedule with the next events at the following link: Click here
Streaming Link (MS Teams): We encourage in-person partecipation. Should you be unable to come here is the link to the event with MICROSOFT TEAMS Click Here
Università Roma Tre
Dipartimento di Matematica e Fisica
Mathematical Analysis
Date: 16 November 2022
Schedule: 16:30 Rome Time
Where: Conference Room Aula 311, Largo San Leonardo Murialdo, 1
Speaker: Luca Martinazzi (Sapienza Università di Roma)
Title: " Critical points of the Moser-Trudinger functional on closed surfaces "
Abstract: Given a 2-dimensional closed surface, we will show that the Moser-Trudinger functional has critical points of arbitrarily high energy. Since the functional is too critical to directly apply to it the known variational methods (in particular the Struwe monotonicity trick), we will approximate it by subcritical ones, which in fact interpolate it to a Liouville-type functional from conformal geometry. Hence our result will also unify and give common results for these two apparently unrelated problems. This is a joint work with F. De Marchis, A. Malchiodi and P-D. Thizy.
Organizing Committee:
Università Roma Tre
Dipartimento di Matematica e Fisica
Further Information: Click here
Streaming Link (MS Teams): Web connection to conference
Eventi