SEMINARI DI GEOMETRIA

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

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

The amenability conjecture for Gromov-hyperbolic groups

Tipo Seminario: 
Relatore: 
Andrea Sambusetti

We will present a classical conjecture on amenability for groups related
to growth. The original result, which is due to Cohen and,
independently, Grigorchuk, dates back to the 80's: a group Q finitely
presented as F/N, where F is a free group, is amenable if and only if
the exponential growth rates  (or _entropies)_ \omega(N) and \omega(F)
of N and F coincide.

Data Seminario: 
Thursday, December 6, 2018
Aula: 
Sala Seminari (Dip. Matematica)
Ora Fine: 
Saturday, January 1, 0000 - 17:00
Affiliazione: 
Università di Roma
Ora Inizio: 
Saturday, January 1, 0000 - 16:00

Transverse invariants from the deformations of Khovanov sl_3 homology

Tipo Seminario: 
Relatore: 
Carlo Collari

In this talk I will describe some invariants for transverse links in  
S^3 (endowed with the symmetric contact structure) arising from the  
deformations of Khovanov sl_3 homology.

I will start with a brief introduction to the theory of transverse  
links in S^3. Afterward, I will recall some known results concerning  
transverse invariants in link homologies. In particular, I will focus  
on the invariants coming from Khovanov-Rozansky homologies, and those   
coming from the deformations of Khovanov homology.

Data Seminario: 
Thursday, October 4, 2018
Aula: 
Sala Seminari (Dip. Matematica)
Ora Fine: 
Saturday, January 1, 0000 - 17:00
Affiliazione: 
Durham University
Ora Inizio: 
Saturday, January 1, 0000 - 16:00

The AJ conjecture for SU(2) and SL(2,C)

Tipo Seminario: 
Relatore: 
Alessandro Malusà

Given a knot K in S^3, one can consider as invariants the A-polynomial and the coloured Jones polynomial. After illustrating the original AJ conjecture, as formulated by Garoufalidis, I will specify its motivation from quantum SU(2)-Chern-Simons theory, and attempt to make sense of the statement that the two invariants mentioned above are classical and quantum in nature, respectively. This opens the question as of whether one can formulate an analogous conjecture for different Lie groups.

Data Seminario: 
Thursday, June 21, 2018
Aula: 
Sala Seminari (Dip. Matematica)
Ora Fine: 
Saturday, January 1, 0000 - 16:00
Affiliazione: 
Aarhus University
Ora Inizio: 
Saturday, January 1, 0000 - 15:00

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

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