Sala Seminari (Dip. Matematica)

Dispersive estimates for the wave equation outside strictly convex obstacles

Relatore: 
Oana Ivanovici

We consider the linear wave equation outside a compact, strictly convex obstacle in R3with smooth boundary and we show that the linear wave flow satisfies the dispersive estimates as in R3 (which is not necessarily the case in higher dimensions). This is joint work with Gilles Lebeau.

Data Seminario: 
Thursday, April 26, 2018
Aula: 
Sala Seminari (Dip. Matematica)
Ora Fine: 
Saturday, January 1, 0000 - 16:00
Affiliazione: 
Universita' di Nizza
Ora Inizio: 
Saturday, January 1, 0000 - 15:00

Rigidity of real hyperbolic lattices: a "natural" approach

Relatore: 
Alessio Savini

Abstract: Rigidity of lattices in semisimple Lie groups has been widely studied so far. One of the most celebrated theorem is Mostow rigidity, which states the following. Assume n bigger or equal than 3. If two complete hyperbolic n-manifolds of finite volume have isomorphic fundamental groups then they are isometric. Equivalently their fundamental groups are conjugated in the group of isometries of the hyperbolic n-space. There are several ways to prove this theorem.

Data Seminario: 
Monday, April 30, 2018
Aula: 
Sala Seminari (Dip. Matematica)
Ora Fine: 
Saturday, January 1, 0000 - 18:00
Affiliazione: 
ETH, Zürich - Università di Bologna
Ora Inizio: 
Saturday, January 1, 0000 - 16:30

Moduli of Weierstrass fibrations.

Relatore: 
Giovanni Inchiostro

We study the the moduli space of KSBA stable pairs (X,sS+\sum a_i F_i), consisting of a Weierstrass fibration X, its section S, and some fibers F_i. We find a compactification which is a DM stack, and we prove that there are wall-crossing morphisms when the weights s and a_i change. This recovers the work of Ascher and Bejleri in the case in which s=1 and the one of La Nave when s=1 and a_i=0. 

Data Seminario: 
Thursday, May 31, 2018
Aula: 
Sala Seminari (Dip. Matematica)
Ora Fine: 
Saturday, January 1, 0000 - 17:00
Affiliazione: 
Brown University
Ora Inizio: 
Saturday, January 1, 0000 - 16:00

Relative quasimaps and quasimap quantum Lefschetz

Relatore: 
Luca Battistella

Quasimaps provide a compactification of the space of maps from smooth curves to a GIT quotient; Ciocan-Fontanine and Kim used them to prove beautiful wall-crossing formulae, comparing the resulting invariants with ordinary Gromov-Witten ones. In joint work with Navid Nabijou, we introduce the notion of genus zero relative quasimaps to a toric target X with respect to a smooth (but not necessarily toric) hyperplane section Y, extending work of Gathmann to this setting.

Data Seminario: 
Thursday, May 31, 2018
Aula: 
Sala Seminari (Dip. Matematica)
Ora Fine: 
Saturday, January 1, 0000 - 16:00
Affiliazione: 
Imperial college, London
Ora Inizio: 
Saturday, January 1, 0000 - 15:00

Analysis of the experiment defining the dielectric constant

Relatore: 
J. Rauch

The dielectric constant is defined by an experiment with an infinite slab of dielectric between two infinite oppositely charged plates.  This talk describes the surprisingly delicate theorem that the physicists formula for the electrostatic potential of this idealized experiment is the limit, as the size tends to infinity, of finite size experiments.  Joint work with L, Ridgway SCOTT.

Data Seminario: 
Thursday, April 26, 2018
Aula: 
Sala Seminari (Dip. Matematica)
Ora Fine: 
Saturday, January 1, 0000 - 17:00
Affiliazione: 
Michigan U.
Ora Inizio: 
Saturday, January 1, 0000 - 16:00

Scomposizioni acilindriche: esempi geometrici e proprietà di crescita

Relatore: 
Filippo Cerocchi

Abstract:  Ricorderemo la nozione di scomposizione acilindrica di un gruppo discreto. Forniremo una serie di esempi e di criteri (rilevanti dal punto di vista topologico e geometrico) che garantiscano l'esistenza di tali scomposizioni. Enunceremo e giustificheremo una versione quantitativa del teorema di sotto(semi)gruppo libero e ne spiegheremo la rilevanza ai fini dello studio delle varietà Riemanniane di entropia e diametro limitati. 

Sito web: http://people.dm.unipi.it/babygeometri/

Data Seminario: 
Tuesday, April 17, 2018
Aula: 
Sala Seminari (Dip. Matematica)
Ora Fine: 
Saturday, January 1, 0000 - 11:00
Affiliazione: 
Università di Roma La Sapienza
Ora Inizio: 
Saturday, January 1, 0000 - 09:30

Entropia minimale di 3-varietà

Relatore: 
Erika Pieroni

Abstrat: In questo seminario introdurremo la nozione di entropia minimale di una varietà.

Proseguiremo calcolando l’entropia minimale di una qualsiasi 3-varietà orientabile, a partire dal dato della sua scomposizione in primi e della scomposizione JSJ di ogni componente irriducibile; in particolare, dimostreremo che l’entropia minimale è additiva rispetto ad entrambe le scomposizioni.

Data Seminario: 
Monday, April 16, 2018
Aula: 
Sala Seminari (Dip. Matematica)
Ora Fine: 
Saturday, January 1, 0000 - 18:00
Affiliazione: 
Università di Roma La Sapienza
Ora Inizio: 
Saturday, January 1, 0000 - 16:30

Purely unrectifiable metric spaces and perturbations of Lipschitz functions

Relatore: 
David Bate
Abstract. We give characterisations of purely $n$-unrectifiable subsets $S$ of a complete metric space $X$ with finite Hausdorff $n$-measure by studying arbitrarily small perturbations of Lipschitz functions $f\colon X \to R^m$. In one such characterisation it is shown that, if $S$ has positive lower density almost everywhere, a typical $f$ (with respect to the supremum norm) has ${\mathcal H}^n(f(S))=0$. Conversely, if $E\subset X$ is $n$-rectifiable with ${\mathcal H}^n(E)>0$, a typical $f$ has ${\mathcal H}^n(f(E))>0$.
Data Seminario: 
Wednesday, May 16, 2018
Aula: 
Sala Seminari (Dip. Matematica)
Ora Fine: 
Saturday, January 1, 0000 - 18:00
Affiliazione: 
Universita' di Helsinki
Ora Inizio: 
Saturday, January 1, 0000 - 17:00

Structured deformations of continua: theory and applications

Relatore: 
Marco Morandotti
Abstract. Structured deformations provide a multiscale geometry that captures the contributions at the microlevel of both smooth geometrical changes and disarrangements at submicroscopic levels. Due to this versatility, they turn out to be a powerful tool to describe the deformations of bodies in a variety of settings. In this seminar, I will present the basic theory of structured deformations, alongside with some applications.
Data Seminario: 
Wednesday, April 18, 2018
Aula: 
Sala Seminari (Dip. Matematica)
Ora Fine: 
Saturday, January 1, 0000 - 18:00
Affiliazione: 
TUM Monaco
Ora Inizio: 
Saturday, January 1, 0000 - 17:00

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