Sala Seminari (Dip. Matematica)

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 23, 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

Pretzel links, mutation, and the slice-ribbon conjecture

Tipo Seminario: 
Relatore: 
Paolo Aceto

We show that the mutant 2-component pretzel links P(p,q,-q,-p) and P(p,q,-p,-q) are not concordant for any distinct odd integers p and q greater than 1. As a corollary, we obtain a proof of the  slice-ribbon conjecture for 4-stranded 2-component pretzel links. In order to distinguish mutant links up to concordance we consider 3-fold branched covers and use an obstruction based on Donaldson's diagonalization theorem. This is joint work with Min Hoon Kim, JungHwan Park and Arunima Ray.

Data Seminario: 
Wednesday, May 16, 2018
Aula: 
Sala Seminari (Dip. Matematica)
Ora Fine: 
Saturday, January 1, 0000 - 16:30
Affiliazione: 
Rényi Institute (Budapest)
Ora Inizio: 
Saturday, January 1, 0000 - 15:30

TBA

Relatore: 
Carlo Collari
Data Seminario: 
Wednesday, May 9, 2018
Tipo Seminario: 
Aula: 
Sala Seminari (Dip. Matematica)
Ora Inizio: 
Saturday, January 1, 0000 - 15:30
Ora Fine: 
Saturday, January 1, 0000 - 16:30

Infinity structures and higher products in rational homotopy theory

Relatore: 
José Manuel Moreno-Fernández

Abstract: The goal of this talk is to understand how L-infinity structures on the rational homotopy groups of a simply connected space behave with respect to the higher Whitehead products. To do so, I will give a self-contained introduction to the relevant facts of rational homotopy theory, via examples, computations and intuition.

If time permits, I will sketch how cohomology algebras over a field, endowed with an A-infinity algebra structure, behave with respect to the higher Massey products. 

 

Data Seminario: 
Monday, April 9, 2018
Aula: 
Sala Seminari (Dip. Matematica)
Ora Fine: 
Saturday, January 1, 0000 - 18:00
Affiliazione: 
Universidad de Málaga
Ora Inizio: 
Saturday, January 1, 0000 - 16:30

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