Sala Seminari (Dip. Matematica)

Seminario di Algebra e Teoria dei numeri - Solvable primitive extensions

Relatore: 
Chandan Dalawat

Abstract: A finite separable extension E of a field F is called primitive if there are no intermediate extensions. It is called solvable if the group Gal(Ê |F) of automorphisms of its galoisian closure Ê over F is solvable.  What are the solvable primitive extensions of F ?  This  problem goes back to Évariste Galois; we show how some recent work complements his insights.

Data Seminario: 
Friday, December 1, 2017
Aula: 
Sala Seminari (Dip. Matematica)
Ora Fine: 
Saturday, January 1, 0000
Affiliazione: 
Harish-Chandra Research Institute
Ora Inizio: 
Saturday, January 1, 0000

Optimal partitions.

Relatore: 
Edouard Oudet

ABSTRACT. We present recent numerical approaches dedicated to the identification
of optimal partitions associated to geometrical costs. We focus our
presentation on 2D surfaces and full 3D problems.

Data Seminario: 
Wednesday, December 13, 2017
Aula: 
Sala Seminari (Dip. Matematica)
Ora Fine: 
Saturday, January 1, 0000
Affiliazione: 
Centro De Giorgi
Ora Inizio: 
Saturday, January 1, 0000

Variational approximations and relaxations of the Steiner problem

Relatore: 
Mauro Bonafini
Abstract. In this talk we focus our attention on problems involving one dimensional sets, using as guiding example the Euclidean Steiner tree problem. We first reformulate the problem over a suitable family of rank one tensor valued measures and then we take two different perspectives. In the first case we focus on the planar setting and provide a variational approximation via Gamma convergence by means of functionals of phase transition type.
Data Seminario: 
Wednesday, December 6, 2017
Aula: 
Sala Seminari (Dip. Matematica)
Ora Fine: 
Saturday, January 1, 0000
Affiliazione: 
Universita' di Trento
Ora Inizio: 
Saturday, January 1, 0000

Asymptotic planar N-bubble

Relatore: 
Giacomo Del Nin
Abstract. We consider in the plane a fixed finite number N of "bubbles", that is disjoint finite perimeter sets which possibly share portions of their boundaries, and look for configurations that minimize, under a volume constraint, the total weighted length of their boundaries: the interface between each bubble and the exterior is given weight 1 while the interface between any two bubbles is given weight $2-\varepsilon$. We are interested in the case when $\epsilon$ converges to 0: we prove that minimizing
Data Seminario: 
Wednesday, November 22, 2017
Aula: 
Sala Seminari (Dip. Matematica)
Ora Fine: 
Saturday, January 1, 0000
Affiliazione: 
Universita' di Pisa
Ora Inizio: 
Saturday, January 1, 0000

Branched transportation: stability and new models.

Relatore: 
Andrea Marchese
Abstract. Models involving branched structures are employed to describe several supply-demand systems such as the structure of the nerves of a leaf, the system of roots of a tree, or the nervous and the cardiovascular systems. Given a flow that transports a given mass distribution $\mu^-$ onto a target distribution $\mu^+$, along a 1-dimensional network, the transportation cost per unit length is proportional to a concave power $\alpha \in (0,1)$ of the intensity of the flow. This favors grouping of the particles' trajectories and prevents diffusion.
Data Seminario: 
Wednesday, November 15, 2017
Aula: 
Sala Seminari (Dip. Matematica)
Ora Fine: 
Saturday, January 1, 0000
Affiliazione: 
University of Zurich
Ora Inizio: 
Saturday, January 1, 0000

Optimal Interpolation Formulas in W_2^{(m,m-1)} space

Relatore: 
Samandar Babaev

In this talk, using S.L.Sobolev’s method, optimal interpolation formulas are constructed in W_{2} ^(m,m1) (0,1) space. Explicit formulas for coefficients of optimal interpolation formulas are obtained. Some numerical results are presented.

Data Seminario: 
Wednesday, November 8, 2017
Aula: 
Sala Seminari (Dip. Matematica)
Ora Fine: 
Saturday, January 1, 0000
Affiliazione: 
Bukhara State University, Uzbekistan
Ora Inizio: 
Saturday, January 1, 0000

Minimal volume hyperbolic 4-manifolds

Tipo Seminario: 

Since the volume of a hyperbolic manifold is often regarded as a measure of its complexity, it is interesting to study the examples of minimal volume.
The 2 and 3-dimensional cases are well understood.
In dimension four there is an abundance of examples, but we are far from classifying them. In this talk, we will survey all known examples of minimal volume hyperbolic 4-manifolds and prove that these fall into three commensurability classes. This is joint work with Stefano Riolo.
 

Data Seminario: 
Thursday, November 2, 2017
Relatore: 
Leone Slavich
Ora Fine: 
Saturday, January 1, 0000
Aula: 
Sala Seminari (Dip. Matematica)
Ora Inizio: 
Saturday, January 1, 0000

A Hele-Shaw tumor growth model as a gradient flow.

Relatore: 
Simone Di Marino
Abstract. In 2014 Perthame, Quiroz and Vasquez unite two types of modeling of tumor growth into a unique framework of reaction-diffusion type where the diffusive term is $\Delta p(\rho)$ and $p(\rho)=\rho^m$. The stiff limit $m \to \infty$ is in particular a Hele-Shaw type problem: we find a gradient flow formulation of this problem, namely it is the gradient flow of the negative mass with respect to the Wasserstein-Fisher-Rao distance, discovered simultaneously by many authors in the last years.
Data Seminario: 
Wednesday, November 8, 2017
Aula: 
Sala Seminari (Dip. Matematica)
Ora Fine: 
Saturday, January 1, 0000
Affiliazione: 
Scuola Normale Superiore
Ora Inizio: 
Saturday, January 1, 0000

On Aharonov-Bohm operators with moving poles

Relatore: 
Veronica Felli

In this talk, I will present some results in collaboration with L. Abatangelo
(Milano-Bicocca), L. Hillairet (Orléans), C. Léna (Torino),  B. Noris
(Amiens), M. Nys (Torino), concerning the behavior of the eigenvalues of
Aharonov-Bohm operators with one moving pole or two colliding
poles. In both cases of poles moving inside the domain and approaching
the boundary, the rate of the eigenvalue variation is estimated in
terms of the vanishing order of some limit eigenfunction. An accurate

Data Seminario: 
Tuesday, November 7, 2017
Aula: 
Sala Seminari (Dip. Matematica)
Ora Fine: 
Saturday, January 1, 0000
Affiliazione: 
Università di Milano bicocca
Ora Inizio: 
Saturday, January 1, 0000

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