Sala Seminari (Dip. Matematica)

Equivariant hyperbolization and applications

Tipo Seminario: 
Relatore: 
Danny Ruberman

Given a closed 3-manifold Y with the action of a finite group G, we show how to find a closely related hyperbolic G-manifold Y’. The two manifolds are related by an invertible equivariant homology cobordism; a cobordism from Y to Y’ is invertible if there is a second cobordism from Y’ to Y such that the union of the two along Y’ is a product cobordism.  I will give a collection of applications in 3 and 4-dimensional topology. (Joint work with Dave Auckly, Hee Jung Kim, and Paul Melvin.)

Data Seminario: 
Thursday, November 23, 2017
Aula: 
Sala Seminari (Dip. Matematica)
Ora Fine: 
Saturday, January 1, 0000 - 17:00
Affiliazione: 
Brandeis University
Ora Inizio: 
Saturday, January 1, 0000 - 16:00

The compressible Euler equations: Riemann problems and non-uniqueness

Tipo Seminario: 
Relatore: 
Elisabetta Chiodaroli
Abstract. In this talk we discuss some applications of the method of convex integration to the compressible Euler system of gas dynamics in two space dimensions. This leads to the construction of infinitely many non-standard solutions even in the case of classical Riemann data. We also show some recent studies meant at visualizing numerically such non-standard solutions.
Data Seminario: 
Wednesday, October 11, 2017
Aula: 
Sala Seminari (Dip. Matematica)
Ora Fine: 
Saturday, January 1, 0000 - 18:00
Affiliazione: 
Universita' di isa
Ora Inizio: 
Saturday, January 1, 0000 - 17:00

Rohlin’s theorem and non-simply connected 4-manifolds

Tipo Seminario: 
Relatore: 
Danny Ruberman

Most applications of gauge theory in 4-dimensional topology are concerned with simply-connected manifolds with non-trivial second homology. I will discuss the opposite situation, first describing the classical Rohlin invariant for manifolds with first homology = Z and vanishing second homology. I will give an interpretation in terms of a Seiberg-Witten theory, with an unusual index-theoretic correction term. I will discuss recent work with Jianfeng Lin and Nikolai Saveliev giving a new formula for this invariant in terms of monopole homology.

Data Seminario: 
Thursday, October 5, 2017
Aula: 
Sala Seminari (Dip. Matematica)
Ora Fine: 
Saturday, January 1, 0000 - 16:00
Affiliazione: 
Brandeis University
Ora Inizio: 
Saturday, January 1, 0000 - 15:00

A weak universality result for the parabolic Anderson model

Relatore: 
Nicolas Perkowski

Abstract: We consider a class of nonlinear population models on a two-dimensional lattice which are influenced by a small random potential, and we show that on large temporal and spatial scales the population density is well described by the continuous parabolic Anderson model, a linear but singular stochastic PDE. The proof is based on a discrete formulation of paracontrolled distributions on unbounded lattices which is of independent interest because it can be applied to prove the convergence of a wide range of lattice models. This is joint work with Jörg Martin.

Data Seminario: 
Tuesday, September 26, 2017
Aula: 
Sala Seminari (Dip. Matematica)
Ora Fine: 
Saturday, January 1, 0000 - 09:15
Affiliazione: 
Humboldt-Universität zu Berlin
Ora Inizio: 
Saturday, January 1, 0000 - 08:15

On corks with low shadow-complexity

Tipo Seminario: 
Relatore: 
Hironobu Naoe

A cork is a contractible Stein domain that gives arise to exotic pairs of 4-manifolds. The first example was found by Akbulut. It is known that any two exotic, simply-connected, closed 4-manifolds are related by a cork twist. We show that there are no corks having shadow-complexity zero. We also show that there are infinitely many corks having shadow-conplexity 1 and 2. 

Data Seminario: 
Thursday, October 12, 2017
Aula: 
Sala Seminari (Dip. Matematica)
Ora Fine: 
Saturday, January 1, 0000 - 16:00
Affiliazione: 
Tohoku University, Japan
Ora Inizio: 
Saturday, January 1, 0000 - 15:00

Binomial edge ideals

Relatore: 
Dott.Francesco Strazzanti

ABSTRACT:

In the last decades the connections between commutative algebra and combinatorics have been extensively explored. It is interesting to study classes of ideals in a polynomial ring associating with them combinatorial objects, such as simplicial complexes, graphs, clutters or polytopes.

In this talk we are interested in the so-called binomial edge ideals, which are ideals generated by binomials corresponding to the edges of a finite simple graph G. They can be viewed as a generalization of the ideal of 2-minors of a generic matrix with two rows.

Data Seminario: 
Monday, September 11, 2017
Aula: 
Sala Seminari (Dip. Matematica)
Ora Fine: 
Saturday, January 1, 0000 - 15:00
Affiliazione: 
University of Sevilla
Ora Inizio: 
Saturday, January 1, 0000 - 14:00

The quantum conditional Entropy Power Inequality

Relatore: 
Giacomo De Palma
Abstract. The Entropy Power Inequality states that the Shannon differential entropy of the convolution of two probability densities in R^n with given entropies is minimum when they are both Gaussian. This functional inequality is fundamental in information theory and was conjectured by C. Shannon himself, although he only proved that Gaussian densities are critical points; a full proof was later given by A. Stam, using an interpolation argument along the heat semigroup.
Data Seminario: 
Tuesday, September 19, 2017
Aula: 
Sala Seminari (Dip. Matematica)
Ora Fine: 
Saturday, January 1, 0000 - 17:00
Affiliazione: 
QMATH, University of Copenhagen
Ora Inizio: 
Saturday, January 1, 0000 - 16:00

Chemical reaction networks: deterministic and stochastic models

Relatore: 
Daniele Cappelletti

Chemical reaction networks are mathematical models used in
biochemistry, as well as in other fields. Specifically, the time
evolution of a system of biochemical reactions are modelled either
deterministically, by means of a system of ordinary differential
equations, or stochastically, by means of a continuous time Markov
chain. It is natural to wonder whether the dynamics of the two modelling
regimes are linked, and whether properties of one model can shed light
on the behavior of the other one. In this talk some connections will be

Data Seminario: 
Tuesday, July 4, 2017
Aula: 
Sala Seminari (Dip. Matematica)
Ora Fine: 
Saturday, January 1, 0000 - 11:00
Affiliazione: 
University of Wisconsin - Madison
Ora Inizio: 
Saturday, January 1, 0000 - 10:00

Introduction to interacting particle systems

Relatore: 
Michel Nassif

Interacting particle systems is a recently developed field in
the theory of Markov processes with many applications: particle systems
have been used to model phenomena ranging from traffic behaviour to spread
of infection and tumour growth. We introduce this field through the study
of the simple exclusion process. We will construct the generator of this
process and we will give a convergence result of the spatial particle
density to the solution of the heat equation. We will also discuss a

Data Seminario: 
Tuesday, June 27, 2017
Aula: 
Sala Seminari (Dip. Matematica)
Ora Fine: 
Saturday, January 1, 0000 - 12:15
Affiliazione: 
ENS Rennes
Ora Inizio: 
Saturday, January 1, 0000 - 11:15

Averaging along irregular curves and regularization of ODEs

Relatore: 
Remi Catellier

Paths of some stochastic processes such as fractional Brownian Motion have some amazing regularization properties. It is well known that in order to have uniqueness in differential systems such as

dy_t = b(y_t) dt,

Data Seminario: 
Tuesday, June 27, 2017
Aula: 
Sala Seminari (Dip. Matematica)
Ora Fine: 
Saturday, January 1, 0000 - 11:00
Affiliazione: 
Université de Nice Sophia-Antipolis
Ora Inizio: 
Saturday, January 1, 0000 - 10:00

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