In order to assess experimentally the stability of algorithms for the solution of systems of linear equations, it is typically desirable to have a certain degree of control over the condition number of the test matrices being used. If the tests are…
Eventi
CHE COS’È UN RIEMPIMENTO SIMPLETTICO – Edoardo Fossati (SNS Pisa)
Titolo: CHE COS’È UN RIEMPIMENTO SIMPLETTICO Abstract: In questo seminario verranno introdotti alcuni concetti che stanno alla base della topologia di contatto. Vedremo come rappresentare oggetti 4-dimensionali e studiare problemi complessi armati…
Metric Lie groups – Sebastiano Nicolussi Golo (Università di Padova)
The objects of the talk are locally compact metric spaces that are isometrically homogeneous. I will discuss their quasi-isometric classification and the characterization of those spaces that admit dilations. They are not assumed to be length…
On Blaschke-Santalo’ diagrams involving the torsional rigidity and the first eigenvalue of the Dirichlet Laplacian – Ilaria Lucardesi (Institut Elie Cartan de Lorraine)
A Blaschke-Santalo’ diagram is the range of a vector shape functional $(F_1,F_2)$ in $\mathbb R^2$. The determination of such attainable set amounts to completely characterize the relation between $F_1$ and $F_2$. In this talk I will present some…
Massimo volume di poliedri iperbolici – Giulio Belletti (SNS Pisa)
In questo seminario esporrò la dimostrazione del teorema sul massimo volume dei poliedri iperbolici, introdotta nello scorso seminario. La dimostrazione si basa su un attento studio delle possibili degenerazioni che un poliedro può subire in seguito…
Vafa-Witten formulas and generalizations – Lothar Göttsche (ICTP, Trieste)
25 years ago Vafa and Witten predicted generating functions for the Euler numbers of the moduli spaces of sheaves on algebraic surfaces. In this talk, I review joint work with Martijn Kool to interpret and check these predictions in terms of virtual…
On the motive of zero-dimensional Quot schemes on a curve – Barbara Fantechi (SISSA, Trieste)
This is a report on joint work with Bagnarol and Perroni, available at arxiv:1907.00826. For any locally free coherent sheaf on a fixed smooth projective curve, we study the class, in the Grothendieck ring of varieties, of the Quot scheme that…
A rectifiability result for sets of finite perimeter in Carnot groups – Sebastiano Don (Universita’ di Padova)
After an introduction to the regularity problem for sets of finite perimeter in Carnot groups, we prove that the reduced boundary of a set of finite perimeter in a Carnot group can be covered by a countable union of sets satisfying a “cone…
Il massimo volume dei poliedri iperbolici – Giulio Belletti (SNS)
Qual è il volume massimo dei poliedri iperbolici con combinatoria fissata? Un risultato classico dice che il massimo volume ottenuto dai simplessi iperbolici è quello del simplesso regolare con tutti i vertici all’infinito. Purtroppo un risultato…
Smoothing of a reducible $I$-surface – Sönke Rollenske (Philipps-Universität Marburg)
The moduli space of stable surfaces is a modular compactification of the Gieseker moduli space of (canonical models of) surfaces of general type but has components consisting solely of non-smoothable surfaces. I will construct a smoothing of a…