Dipartimento di Matematica e Informatica

Modelli matematici di crescita e motilità cellulare - Luigi Preziosi (Politecnico di Torino)

Stumbo Fabio — 2016-03-07T11:09:46Z

Si è dimostrato ultimamente che le caratteristiche meccaniche della
cellula, del suo nucleo e dell'interazione con l'ambiente circostante
giocano un ruolo importante nella determinazione del comportamento e del
moto delle cellule in strutture fibrose reali e artificiali. Dal punto
di vista applicativo capire questo processo riveste una grande
importanza da una parte per descrivere il processo di diffusione di
metastasi tumorali e dall'altra per ottimizzare le metodologie di
crescita tissutale.
Dal punto di vista matematico, il problema può essere affrontato
utilizzando diversi modelli matematici, dalla scala microscopica
molecolare alla scala macroscopica tissutale. Anzi l'utilizzo di modelli
multiscala risulta essere una necessità intrinseca del problema
biomedico. Finalità del seminario è quindi quella di presentare diversi
modelli matematici sviluppati per descrivere i fenomeni di migrazione ed
aggregazione cellulare.

Piece-wise Constant Image Segmentation with a Deep Image Prior Approach

Rizzati Michele — 2024-05-16T08:54:49Z

La segmentazione di immagini è un tema di ricerca molto vivo in svariati ambiti di applicazione

(computer vision, image processing, medical imaging). Tale problema può essere formulato

attraverso la minimizzazione del funzionale di Mumford-Shah, uno degli approcci più utilizzati

in questo ambito. Negli anni recenti nuove tecniche sono state studiate, basate su approcci

di tipo Deep Learning. In questo seminario proponiano un approccio non supervisionato per la

segmentazione semantica basato sul framework Deep Image Prior: il funzionale di Mumford Shah

viene riparametrizzato attraverso i pesi di una rete convolutoria. I primi esperimenti, eseguiti su

immagini "naturali" e mediche mostrano come questo approccio fornisca risultati molto affidabili,

anche in presenza di rumore. Porremmo anche le basi per l'estensione al modello di Ambrosio-Tortorelli.

Tutti gli interessati sono invitati a partecipare.

On a degenerate problem in the Calculus of Variations - Pierre Bousquet (Università di Tolosa, FRANCIA)

Stumbo Fabio — 2016-05-20T16:30:05Z

Abstract : We present a scalar problem in the multiple integrals 
calculus of variations with a convex  Lagrangian which is neither smooth 
nor strictly convex. We describe the regularity of the solutions and we 
address the uniqueness problem. This is a  joint work with Guy Bouchitté 
and Cedric Galusinski.

Seminari di Analisi @ Unife - Wavefronts for degenerate diffusion-convection reaction equations

Rizzati Michele — 2021-04-26T09:46:21Z

Title: Wavefronts for degenerate diffusion-convection reaction equations

Abstract: We deal with wavefront solutions to a scalar parabolic equation in one spatial dimension.
The equation consists of a convective term, a reaction term (typically of monostable type) and
a vanishing diffusivity. Wavefronts are traveling waves whose profile is globally defined,
non-constant and monotone. The main topic of this talk concerns the existence of such solutions,
their regularity and related properties. In particular, about the regularity, it is highlighted the behaviour
where the diffusivity vanishes.
All results are based on joint work with Corli (Ferrara) and Malaguti (Modena and Reggio Emilia).

Giovedì 29 aprile 2021
Ore 16.00
Diego Berti (Università di Modena e Reggio Emilia)

Il seminario si terra’ in modalità’ telematica e il codice meet per collegarsi e’

https://meet.google.com/dif-qrmm-bgy

Seminario: On the root uncertainty principle

Ferrari Michele — 2016-10-03T09:18:01Z

Speaker: prof. Diogo Oliveira e Silva (Università di Bonn)

Title: On the root uncertainty principle.

Abstract:

This talk will focus on a recent result of Bourgain, Clozel and Kahane. One of its versions states that a real-valued function which equals its Fourier transform and vanishes at the origin necessarily has a root which is larger than c>0, where the best constant c satisfies 0.41

preprint: https://arxiv.org/abs/1602.03366

Transmission conditions arising by homogenisation of Neumann problems - Giovanni Franzina (Indam, Firenze)

Stumbo Fabio — 2018-05-09T15:07:46Z

Seminario di: Analisi Matematica

Descent cohomology - Bachi Mesablishvili (Razmadze Mathematical Institute of Tbilisi State University - Georgia)

Stumbo Fabio — 2016-07-01T11:28:24Z

We introduce and investigate descent cohomology of (co)monads

on arbitrary base category with coefficients in (co)algebras over the (co)monad.

Some homomorphisms between groups of birational transformations - Christian Urech (Univ. di Basilea)

Stumbo Fabio — 2016-07-01T11:24:28Z

To a projective variety X one can associate Bir(X), its group of birational transformations. In this talk we will look at the question, how one can embed Bir(P^n) into groups of birational transformations in higher dimensions.
In particular, I will describe geometrical properties of an example of an embedding of Bir(P^2) into Bir(P^5) by Gizatullin and I will give a classification of certain embeddings of Bir(P^n) into Bir(X), where X is a variety of dimension n+1.

Picard groups of moduli of curves and polarized K3 surfaces - Andrea Di Lorenzo

Stumbo Fabio — 2019-09-30T09:19:43Z

Abstract: The Picard group of a variety, i.e. the group of line bundles that live over it, is an interesting and much studied invariant in algebraic geometry. In particular, the Picard groups of moduli spaces of objects (e.g. smooth curves of fixed genus, quasi-polarized K3 surfaces of fixed degree) have been the subject of a large amount of research in the past thirty years.
In this talk, I will explain how techniques of equivariant intersection theory, applied to certain moduli spaces of complete intersections, can shed some light on two specific questions:
(1) Suppose that the base field has positive characteristic. Is the Picard group of the moduli stack of smooth curves of fixed genus freely generated by the Hodge line bundle?
(2) Do the Noether-Lefschetz elliptic divisors freely generate the integral Picard group of moduli stack of polarized K3 surfaces?
Time permitting, I will show how the same methods can be used in order to compute the classes of some geometrically meaningful divisors on these moduli spaces in terms of the generators of the Picard groups.

Equazioni e soluzioni nell’analisi ‘comune’ cartesiana e nella ‘nuova’ analisi leibniziana - Prof. Niccolò Guicciardini (Università di Bergamo)

Rizzati Michele — 2018-06-28T12:26:14Z

During the seventeenth century, the advent of what were known as the ‘common’ and the ‘new analyses’, changed the mathematical landscape of European mathematics in a deep way. The narrative which is widely accepted is that the seventeenth-century analyses (algebra and calculus), mostly due respectively to Descartes and Leibniz, promoted a transition from geometrical to symbolical methods, from Euclidean proportion theory to equations. It is this change that would have allowed the advent of a more abstract way of practicing mathematics, a way that culminated in the eighteenth century with the algebraic approach to calculus and mechanics promoted by Leonhard Euler and Joseph-Louis Lagrange. In this lecture, I will show that, contrary to the accepted narrative [1], for Descartes, Leibniz and their immediate followers, geometrical interpretation and mechanical constructions still played a crucial role. This is revealed by the way in which they handled equations and how they sought their solutions.

[1] One can read in Morris Kline’s influential, and still fundamental, textbook: ‘Whereas from Greek times until about 1600 geometry dominated mathematics and algebra was subordinate, after 1600 algebra became the basic mathematical subject; in this transposition of roles the calculus was the decisive factor’. Morris Kline, Mathematical Thought from Ancient to Modern Times, New York, Oxford University Press, 1972, p. 323.

The rationality problem for hypersurfaces

Rizzati Michele — 2022-09-21T09:37:32Z

Abstract: I will give an overview on the rationality problem for (very general) hypersurfaces. That is, for which degrees d and dimension n is a very general hypersurface of degree d and dimension n rational, stably rational, or retract rational?

Relatore:Stefan Schreieder (Leibniz Universität Hannover)

Luogo: Aula 5

Data e ora: 29 settembre 2022, ore 14:30

Seminario di Analisi: A Semi-Linear Backward Parabolic Cauchy Problem with Unbounded Coefficients of Hamilton-Jacobi-Bellman Type and Applications to optimal control (Davide Addona)

Foschi Damiano — 2014-04-04T08:52:17Z

Martedi' 8 aprile 2014, ore 11.30 Aula 3, Dipartimento di Matematica e Informatica, via Machiavelli 35

speaker: Davide ADDONA (Universita' di Milano Bicocca)

title: "A Semi-Linear Backward Parabolic Cauchy Problem with Unbounded Coefficients of Hamilton-Jacobi-Bellman Type and Applications to optimal control"

Abstract: We obtain weighted uniform estimates for the gradient of the solutions to a class of linear parabolic Cauchy problems with unbounded coefficients. Such estimates are then used to prove existence and uniqueness of the mild solution to a semi-linear backward parabolic Cauchy problem, where the differential equation is the Hamilton-Jacobi-Bellman equation of a suitable optimal control problem. Via backward stochastic differential equations, we show that the mild solution is indeed the Value Function of the controlled equation and that the feedback law is verified.

Seminario: Invariance under twisting for twisted tensor products of algebras (Florin Panaite)

Ferrari Michele — 2014-09-08T09:45:18Z

Il Prof. Florin Panaite è ospite del Dipartimento di Matematica e Informatica della Università di Ferrara come "Visiting Professor" del GNSAGA (Indam) dal 7 Settembre 2014 fino al 6 Ottobre 2014.

Il Prof. Panaite è disponibile per collaborazione scientifica con tutti gli interessati.

Il Prof. Panaite terrà una serie di seminari.

Il primo seminario si terrà

GIOVEDI' 11 SETTEMBRE alle ore 16.00 in aula 7

e avrà per tema:

"Invariance under twisting for twisted tensor products of algebras"

La valutazione nella didattica

Rizzati Michele — 2022-09-14T10:33:28Z

Per seguire il convegno online: https://www.youtube.com/watch?v=JmTVWWlSl-A

Programma:

14.30 – 14.45. Saluti e introduzione al seminario
14.45 – 15.30. Federica Ferretti – Università di Ferrara
Le prove INVALSI e la didattica della matematica: analisi di
macrofenomeni emersi in sede di valutazione standardizzata
15.30 – 16.15. Alice Lemmo – Università dell’Aquila
La valutazione in matematica ai tempi dell’O.M. 172
16.15 – 17.00. Andrea Maffia – Università di Bologna
Valutare con i giochi da tavolo: possibile?!
17.00 – 17.45. Chiara Giberti – Università di Bergamo
Differenze di cittadinanza in matematica: evidenze dalle prove INVALSI
17.45 – 18.30. Discussione finale

Comitato scientifico organizzatore: Federica Ferretti, Elena Lazzari, Maria Giulia Lugaresi, Anna Pelizzari

Seminario di Geometria: On degenerations of plane Cremona transformations (Jérémy Blanc)

Foschi Damiano — 2014-05-06T10:45:52Z

Speaker: Jérémy Blanc (Università di Basilea)

Title: On degenerations of plane Cremona transformations.

Abstract: "I will present the group of Cremona transformations of the plane and the natural topology we can put on it. The set of maps of some bounded degree is closed, and the natural question that arises is to determine which maps of small degree are limits of maps of higher degree. I will give some answers to this question. This is a joint work with Alberto Calabri."