La teoria geometrica dei gruppi si occupa, come il nome suggerisce, dello studio dei gruppi tramite un approcio di tipo geometrico. Piu` precisamente, ad ogni gruppo si associa uno spazio metrico, tipicamente il rivestimento universale del complesso…
Eventi
On the scaling limit of Onsager’s molecular model for liquid crystals – Yuning Liu (NYU University at Shanghai)
We study the small Deborah number limit of the Doi-Onsager equation for the dynamics of nematic liquid crystals. This is a Smoluchowski-type equation that characterizes the evolution of a number density function, depending upon both particle…
Computational Geometry and Topology for Data Analysis – Daniela Giorgi (CNR, Pisa)
Il seminario introdurrà alcune problematiche classiche dell’analisi di dati digitali multidimensionali, e in particolare di modelli 3D: segmentazione, classificazione, confronto. Vedremo come la geometria e la topologia computazionale si prestino…
Optimal partitions. – Edouard Oudet (Centro De Giorgi)
Wepresentrecentnumericalapproachesdedicatedtotheidentification ofoptimalpartitionsassociatedtogeometricalcosts.Wefocusour presentationon2Dsurfacesandfull3Dproblems.…
Minimal Elastic Networks – Alessandra Pluda
In this talk we will consider planar networks of three curves minimizing a combination of the elastic energy and the length functional. We will prove existence and regularity of minimizers and we will show some properties of the minimal…
Equivariant hyperbolization and applications – Danny Ruberman (Brandeis University)
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…
Functions of fractal bounded variation – Roger Züst
In this talk we introduce a notion of functions of fractal bounded variation. Here, the sup-norm of test functions as used in the classical definition is replaced by the Hoelder norm with respect to some exponent. Characteristic functions of domains…
Asymptotic planar N-bubble – Giacomo Del Nin (Universita’ di Pisa)
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…
On the fractal geometry of the Lagrange and Markov spectra. – Carlos Matheus (Paris XIII)
After the remarkable works of Markov in 1879 and 1880, the Lagrange and Markov spectra (coding arithmetic properties of irrational numbers and indefinite binary quadratic forms) were studied by several authors (including Perron, Hall, Freiman,…
On mixing rates for time-changes of Heisenberg nilflows – Giovanni Forni (University of Maryland)
We construct Bufetov functionals for nilpotent flows on (compact) Heisenberg nilmanifolds. Such functionals were first constructed by Bufetov for Interval Exchange Transformations and Translation flows, and later for horocycle flows by Bufetov and…