Events

Prof. Heinz Hanssmann (University of Utrecht)

“Families of hyperbolic Hamiltonian tori”

Thursday 11 February 2016,  15.00

Dipartimento di Matematica (aula Dal Passo) Università di Roma “Tor Vergata”

Abstract:

In integrable Hamiltonian systems hyperbolic tori form families, parametrised by the actions conjugate to the toral angles. The union over such a family is a normally hyperbolic invariant manifold. Under Diophantine conditions a hyperbolic torus persists a small perturbation away from integrability. Locally around such a torus the normally hyperbolic invariant manifold is the centre manifold of that torus and persists as well. We are interested in `global’ persistence of the normally hyperbolic invariant manifold. An important aspect is how the dynamics behaves at the (topological) boundary. Where the manifold extends to infinity this boundary is empty – this case makes clear that we need the persistence theorem of normally hyperbolic invariant manifolds in the non-compact setting. If the normal hyperbolicity wanes as the boundary is approached we need to ensure that the perturbed dynamics does not come closer to the boundary. This provides the necessary uniform lower bound of normal hyperbolicity to still ascertain persistence under small perturbations. Making use of energy preservation and of Diophantine tori persisting by KAM theory this can be achieved for families of two-dimensional hyperbolic tori.

The workshop “Dynamical systems in logic, complex analysis and ergodic theory” will be held in Pisa, from February 8 until 9, 2016.

For all information see https://pagine.dm.unipi.it/workshoppra/

Wednesday 27th January 2016, h 15:00

Sala Conferenze, Collegio Puteano, Centro De Giorgi, Pisa

Anna Miriam Benini (University of Roma Tor Vergata)

“Permutable entire functions and multiply connnected wandering domains”

Abstract: Let f and g be permutable transcendental entire functions. It is a long standing question whether the Julia sets of f and g are equal. The conjecture is true in the case that f,g are rational functions, and in the transcendental case the main issues are due to the presence of Baker Domains and Wandering Domains. Using a recent analysis of the dynamical behaviour in multiply connected wandering domains, we can make progress by showing that J(f) = J(g) unless (possibly) either f or g has a special type of wandering domains, namely simply connected wandering domain in the fast escaping set. This is joint work with G. Stallard and P. Rippon.

The conference “Renormalization in Dynamics” will be held in Pisa, from April 4 until 8, 2016.

For all information see https://www.crm.sns.it/event/360/

There will be financial support for PhD students and young PostDocs. The deadline for application is 15th January 2016.

Thursday 12th November 2015, h 9:30 Sala Conferenze, Collegio Puteano, Centro De Giorgi, Pisa

Henk Bruin (University of Vienna)

“Sharp mixing rates via inducing with respect to general return times”

Abstract: For non-uniformly expanding maps inducing w.r.t. a general (i.e., not necessarily first) return time to Gibbs Markov maps, we provide sufficient conditions for obtaining sharp estimates for the correlation function. This applies to both the finite and the infinite measure setting. The results are illustrated by non-Markov intervals maps with an indifferent fixed point. This is joint work with Dalia Terhesiu.

Monday 9th November 2015, h 15:00 - 17:00 Aula Seminari (Dipartimento di Matematica, Pisa)

Alfonso Sorrentino (Università di Roma “Tor Vergata”)

“AUBRY-MATHER THEORY FOR TWIST MAPS AND BILLIARDS”

This is a special meeting of the “Mathematical Physics Working Group” of the Mathematical Department of the University of Pisa, and will be of introductory level.

The conference “Geometric Aspects of Modern Dynamics” will be held in Oporto (Portugal) from January 11 until 15, 2016:

https://cmup.fc.up.pt/complexdynamics/

Organizing Committee: Jasmin Raissy (U. Toulouse, France) Helena Reis (U. Porto, Portugal)

Scientific Committee: Marco Abate (U. Pisa, Italy) Alexey Glutsuyk (ENS-Lyon, France) Misha Lyubich (SUNY-SB, US) Julio Rebelo (U. Toulouse, France) Helena Reis (U. Porto, Portugal)

Thursday  03/9/2015, h 16:30 Sala Conferenze (Puteano, Centro De Giorgi)

Mark Pollicott (University of Warwick)

“LINEAR RESPONSE AND PERIODIC ORBITS”

On Thursday 3rd September there will be a special session at the 17th European Women in Maths general meeting in Cortona on “Dynamical aspects of number theory”.  It runs from 10:00 - 13:00, and there will be short talks by Valerie Berthé, Karma Dajani, Charlene Kalle, Henna Koivusalo and Nicola Oswald.

Registration for the conference is unfortunately already closed, but if anyone is nearby and wants to come only for this morning session, I can’t imagine there would be any problem. (I hope this goes without saying, but let me say it anyway, men are obviously welcome to attend the talks too.)

When: Wednesday July 22, 2015, at 11:30

Where: Seminario I, Dept. of Mathematics, Università di Bologna

Who: Francesco Cellarosi (Queen’s University, Canada)

What: Seminar “Recent progress towards Sarnak’s and Chowla’s Conjectures”

Abstract: I will present an overview of Sarnak’s conjecture on the disjointness of the Möbius function from any deterministic sequence and the related Chowla’s conjecture on the self-correlations of the Möbius function. Some progress towards weaker versions of these conjectures have been made recently, and I plan to illustrate them.