Seminari/Colloquia
Pagina 28 di 31
Data | Tipo | Inizio | Fine | Room | Speaker | Provenienza | Titolo |
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09/05/23 | Seminario | 16:00 | 17:00 | 1201 | Giuseppe Pipoli | Università dell'Aquila |
Constant mean curvature hypersurfaces in H^n x R with small planar boundary
Denoting with H^n the n-dimensional hyperbolic space,
we show that constant mean curvature hypersurfaces in
H^n x R with small boundary contained in a horizontal slice
P are topological disks, provided they are contained in one of the two
half-spaces determined by P.
This is the analogous in H^n x R of a result in
R^3 by A. Ros and H. Rosenberg.
The proof is based on geometric and analytic methods : from one side
the constant mean curvature equation is a quasilinear elliptic PDE on
manifolds, to the other the specific geometry of the ambient space
produces some peculiar phenomena.
This talk is based on a joint work with Barbara Nelli.
NB:This talk is part of the activity of the MIUR Excellence Department Project MATH@TOV CUP E83C18000100006 |
02/05/23 | Seminario | 14:30 | 15:30 | 1201 | Veronica Tora | Università di Roma "Tor Vergata" |
Reaction-diffusion equations on graphs for the modelling of the formation of large protein aggregates in Alzheimer’s disease
Link to the abstract
Note: This talk is part of the activity of the MIUR Department of Excellence Project MatMod@TOV (2023-2027) |
28/04/23 | Seminario | 14:30 | 15:30 | 1201 |
"Hartley's Conjecture and development arising"
In the 80s Bryan Hartley conjectured that if the unit group a torsion group algebra FG satisfies a group identity, then FG satisfies a polynomial identity. In this talk we aim to review the most relevant results that arose from its solution and to discuss some recent developments concerning group identities for the set of symmetric units of FG.
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20/04/23 | Seminario | 16:00 | 17:00 | 1201 | Hamza Ounesli | SISSA |
Existence of invariant measures for circle expanding maps of low regularity
It is well known that uniformly expanding circle maps whose derivative is Holder continuous have a unique ergodic invariant probability measure absolutely continuous with respect to Lebesgue. This result was extended by Fan and Jiang in 2001 to maps whose derivative is Dini-integrable. However, there exist counterexamples, both to the existence and to the uniqueness, for C^1 maps for which the derivative is less regular. We show that nevertheless, for any given modulus of continuity, there is a C^1 uniformly expanding map of the circle whose derivative has that modulus of continuity and has an invariant probability measure equivalent to Lebesgue.
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20/04/23 | Seminario | 17:00 | 18:00 | 1201 | Stefano Luzzatto | ICTP |
Existence and non-existence of Physical Measures for doubly intermittent interval maps
We introduce a class of one-dimensional full branch maps which may admit up to two neutral fixed points as well as critical points and/or singularities with unbounded derivative. We give a complete classification of the possible physical measures which may appear (or not), study some other statistical properties, and show that different behaviour can be quite intermingled in parameter space. This is joint work with Douglas Coates and Muhammad Mubarak.
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14/04/23 | Seminario | 14:30 | 15:30 | 1201 |
"Quantum affine algebras: comparing two coproducts"
The quantum affine algebras Uq are Hopf algebras with the coproduct Δ defined by Drinfeld and Jimbo; but they have also a "coproduct" Δv with values in a completion of Uq ⊗ Uq , introduced by Drinfeld for quantm affinizations. While the relation between Δ and the action of the braid group (and also of the weight lattice, which is a subgroup of the braid group) is complicated and involves the R-matrix, Δv is by construction equivariant with respect to the action of the weight lattice.
In this talk I will show that Δv can be obtained as "equivariant limit" of Δ . |
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14/04/23 | Seminario | 16:00 | 17:00 | 1201 |
"On the Picard group of the stack of G-bundles on families of curves"
Given a family of smooth projective curves and an arbitrary connected linear algebraic group G, we investigate the Picard group of the stack of relative G-bundles on the family.
This is a joint work with Roberto Fringuelli. |
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13/04/23 | Seminario | 16:00 | 17:00 | 1101 | Elias Rego | Shenzhen |
On the shadowableness of singular flows
The shadowing property is a landmark of the dynamical systems theory which is deeply related to stability phenomena. Hyperbolicity is a famous source of systems with the shadowing property. Nevertheless, the shadowing property does not hold for systems beyond the hyperbolic ones. Indeed, the Lorenz attractor is a paradigmatic example of non-hyperbolic flow which reassembles several properties of the hyperbolic ones, although it does not satisfy the shadowing property, as it was showed by M. Komuro. Several years later L. Wen and X. Wen extended Komuro's results and proved that a sectional hyperbolic set does not satisfy the shadowing property, unless it is hyperbolic. In this talk, we will push further this discussion and ask whether the non-shadowableness of singular flows is due to the sectional hyperbolicity or it is, in fact, a consequence of existence of attached singulaties. This is a joint work with A. Arbieto, A Lopez and Y. Sanchez.
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05/04/23 | Seminario | 14:00 | 15:00 | 1101 | Bernardo Carvalho | Federal University of Minas Gerais / Tor Vergata / UFMG |
Chaos theory and hyperbolic dynamics
In this talk I will discuss relations between chaotic and hyperbolic systems. More specifically, how we can obtain known results from hyperbolic dynamics using stronger notions of sensitivity to initial conditions. I will briefly explain expansiveness, topological hyperbolicity, cw-expansiveness, cw-hyperbolicity and first-time sensitivity.
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04/04/23 | Seminario | 14:30 | 15:30 | 1201 | Marco Pozza | Università di Roma "Tor Vergata" |
Large Time Behavior of Solutions to Hamilton-Jacobi Equations on Networks
Starting from Namah, Roquejoffre (1999) and Fathi (1998), the large time asymptotic behavior of solutions to Hamilton-Jacobi equations has been extensively investigated by many authors, mostly on smooth compact manifolds or the N-dimensional torus. Following recent development due to Pozza, Siconolfi (to appear), we extended this asymptotic analysis to time dependent problems on networks. The main difference between this and more traditional settings is that, for the well posedness of the evolutive problem on networks, the equation must be coupled with a ”flux limiter”, that is the choice of appropriate constants on each vertex of the network. These constants, among other things, bond from above the time derivatives of any subsolution on the vertices. In this talk we will show how this new condition impact the asymptotic behavior of the solutions to the Hamilton-Jacobi problem on networks.
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