Sala Seminari (Dip. Matematica)

TBA

Relatore: 
Roman Sauer
Data Seminario: 
Wednesday, March 27, 2019
Tipo Seminario: 
Aula: 
Sala Seminari (Dip. Matematica)
Ora Fine: 
Saturday, January 1, 0000 - 16:00
Affiliazione: 
Karlsruhe
Ora Inizio: 
Saturday, January 1, 0000 - 15:00

DECOMPOSABLE CLUTTERS AND A GENERALIZATION OF SIMON’S CONJECTURE

Tipo Seminario: 
Relatore: 
Mina Bigdeli

Each (equigenerated) squarefree monomial ideal in the polynomial ring S =
K[x 1 , . . . , x n ] represents a family of subsets of [n], called a (uniform) clutter. In this
talk, we introduce a class of uniform clutters, called decomposable clutters, whose
associated ideal has linear quotients and hence linear resolution over all fields. We
show that chordality of these clutters guarantees the correctness of a conjecture
raised by R. S. Simon on extendable shellability of d-skeletons of a simplex, for all

Data Seminario: 
Friday, March 8, 2019
Aula: 
Sala Seminari (Dip. Matematica)
Ora Fine: 
Saturday, January 1, 0000 - 16:30
Affiliazione: 
INSTITUTE FOR RESEARCH IN FUNDAMENTAL SCIENCES (IPM), IRAN
Ora Inizio: 
Saturday, January 1, 0000 - 15:30

On the speed of propagation for stochastic Hamilton-Jacobi equations

Relatore: 
Paul Gassiat

Abstract: We study the speed of propagation of initial data for Hamilton-Jacobi equations with multiplicative rough (typically stochastic) time dependence. We first show that, in contrast with the classical (deterministic) case, in general this speed may be infinite as soon as the driving noise has unbounded variation. In the case where the Hamiltonian is convex in the gradient, we show that the range of dependence is bounded by a multiple of the length of a piecewise linear path obtained by connecting the successive extrema of the original path.

Data Seminario: 
Monday, February 18, 2019
Aula: 
Sala Seminari (Dip. Matematica)
Ora Fine: 
Saturday, January 1, 0000 - 12:30
Affiliazione: 
Université Paris Dauphine
Ora Inizio: 
Saturday, January 1, 0000 - 11:30

On the flow of elastic networks

Abstract. In this talk I will discuss a long-time existence result for the elastic flow of a three network in $R^n$. The evolution is such that the sum of the elastic energies of the three curves plus their weighted lengths decrease in time. Natural boundary conditions are considered at the boundary of the curves and at the triple junction. This is joint work with Anna Dall'Acqua and Chun-Chi Lin.
Data Seminario: 
Wednesday, March 13, 2019
Relatore: 
Paola Pozzi
Ora Fine: 
Saturday, January 1, 0000 - 18:00
Aula: 
Sala Seminari (Dip. Matematica)
Ora Inizio: 
Saturday, January 1, 0000 - 17:00

Some recent results in the study of fractional mean curvature flow

Relatore: 
Eleonora Cinti
Abstract. We study a geometric flow driven by the fractional mean curvature. The notion of fractional mean curvature arises naturally when performing the first variation of the fractional perimeter functional. More precisely, we show the existence of surfaces which develope neckpinch singularities in any dimension $n\ge 2$. Interestingly, in dimension $n=2$ our result gives a counterexample to Grayson Theorem for the classical mean curvature flow. We also present a very recent result, in the volume preserving case, establishing convergence to a sphere.
Data Seminario: 
Wednesday, March 6, 2019
Aula: 
Sala Seminari (Dip. Matematica)
Ora Fine: 
Saturday, January 1, 0000 - 18:00
Affiliazione: 
Universita' di Bologna
Ora Inizio: 
Saturday, January 1, 0000 - 17:00

Existence and uniqueness for crystalline mean curvature flows with general mobilities

Relatore: 
Marcello Ponsiglione

Abstract. 

In this seminar we will discuss weak formulations for crystalline mean curvature flows, providing existence and uniqueness of the geometric evolution up to fattening.  

In particular, we show that the Almgren-Taylor-Wang scheme starting from any given initial set converges, up to fattening, to a unique flat flow. These results are in collaboration with A. Chambolle, M. Morini and M. Novaga.

Data Seminario: 
Wednesday, February 27, 2019
Aula: 
Sala Seminari (Dip. Matematica)
Ora Fine: 
Saturday, January 1, 0000 - 18:00
Affiliazione: 
Universita' di Roma La Sapienza
Ora Inizio: 
Saturday, January 1, 0000 - 17:00

Varietà iperboliche compatte che non ammettono strutture spin

Relatore: 
Bruno Martelli

Per un teorema di Deligne - Sullivan del 1977, qualsiasi n-varietà iperbolica compatta è "virtualmente stabilmente parallelizzabile", cioè ha un rivestimento finito che è "stabilmente parallelizzabile" (il suo fibrato tangente diventa banale se sommato con un opportuno fibrato banale). Una varietà stabilmente parallelizzabile in particolare ammette una struttura spin. Ricordiamo che tutte le 2- e 3-varietà orientabili sono stabilmente parallelizzabili ("stabilmente" è necessario solo in dimensione 2), quindi questo teorema è rilevante solo in dimensione n>=4.

Data Seminario: 
Wednesday, February 6, 2019
Aula: 
Sala Seminari (Dip. Matematica)
Ora Inizio: 
Saturday, January 1, 0000 - 15:00
Ora Fine: 
Saturday, January 1, 0000 - 16:00

Seminario di Logica e Analisi - Embedding C*-algebras into the Calkin algebra

Relatore: 
Andrea Vaccaro - Università di Pisa & York University

Abstract: Given a complex (not necessarily separable) Hilbert space H, a
C*-algebra is a self-adjoint, norm-closed subalgebra of B(H), the algebra
of all linear bounded operators from H into itself. The Calkin algebra
Q(H) is the quotient of B(H) modulo the ideal of compact operators K(H),
for H a complex separable infinite dimensional Hilbert space. It might not
seem obvious from the definition above, but Q(H) is indeed a C*-algebra.
This structure has always been object of intense studies by researchers in

Data Seminario: 
Monday, February 4, 2019
Aula: 
Sala Seminari (Dip. Matematica)
Ora Inizio: 
Saturday, January 1, 0000 - 15:00
Ora Fine: 
Saturday, January 1, 0000 - 16:00

Transizione geometrica in dimensione quattro

Tipo Seminario: 
Relatore: 
Stefano Riolo

Negli anni '70, Thurston introduce il concetto di "degenerazione" di strutture iperboliche su 3-varietà. Questo avrà un ruolo nella dimostrazione del celebre "Teorema dell'orbifold".
Nella sua tesi del 2011, Danciger mostra che spesso in presenza di tale degenerazione c'è anche "transizione" a strutture anti de Sitter (AdS). Per "transizione geometrica", si intende un processo continuo che permette di passare da una geometria a un'altra, come ad esempio la familiare transizione iperbolico-euclideo-sferica all'interno della geometria proiettiva.

Data Seminario: 
Wednesday, January 30, 2019
Aula: 
Sala Seminari (Dip. Matematica)
Ora Fine: 
Saturday, January 1, 0000 - 15:30
Affiliazione: 
Neuchatel
Ora Inizio: 
Saturday, January 1, 0000 - 14:30

Generalised solutions via set optimization of Hamilton-Jacobi equation for multi objective cost

Tipo Seminario: 
Relatore: 
Daniela Visetti

Abstract. Vedere file allegato. 

Data Seminario: 
Thursday, January 24, 2019
Aula: 
Sala Seminari (Dip. Matematica)
Ora Fine: 
Saturday, January 1, 0000 - 11:00
Affiliazione: 
Free University of Bozen-Bolzano
Ora Inizio: 
Saturday, January 1, 0000 - 10:00

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