[CvGmt News] [Notiziario] [Settimanale] notiziario settimanale

[Giulia Curciarello]

lunedi' - 08-03-2004 (17:00 - Sala Seminari) :

Yi Zhang University, P.R. China.
Cardinal invariant of symmetric groups
argomento: Logica Matematica
abstract:
In my talk I will present two cardinal invariants in Sym(N),
namely the least cardinality of maximal cofinitary groups
and the cofinality of Sym(N),
which were generated from the work of J.Truss, P.Cameron, P.Neumann,
D.Macpherson, S.Thomas and myself.
I will discuss their possible cardinalities and order
relationship, and I will ask several open questions in the area.

lunedi' - 08-03-2004 (14:30 - Sala Seminari del C. di Ricerca Mat. Ennio De
Giorgi palazzo Puteano) :
Joao Lopes-Dias, (Instituto Superior Tecnico Lisbona Portogallo)
Multidimensional continued fractions, renormalisation and KAM theory
argomento: Analisi Matematica
abstract:
We construct a renormalisation scheme for vector fields on the d-torus and
Hamiltonian flows, based on a multidimensional continued fractions algorithm
of a d-dimensional vector. The convergence of this renormalisation to a
trivial limit set implies some results of Kolmogorov-Arnold-Moser (KAM) type
for the stability of diophantine
quasi-periodic motion.

mercoledi' - 10-03-2004 (15:30 - Sala Riunioni) : Simona Settepanella

Coomologia dei gruppi delle trecce pure generalizzati e fibra di
argomento: Geometria
abstract:
In questo seminario ci proponiamo di definire gli arrangiamenti di
iperpiani, con particolare attenzione agli arrangiamenti dati dagli
iperpiani di riflessione definiti dai gruppi di Coxeter finiti.
Descriveremo, inoltre, un complesso algebrico, noto come "complesso di
Salvetti", e ne mostreremo l'applicazione al calcolo della coomologia dei
gruppi delle trecce pure.Inoltre, per ciascuno di questi gruppi, mostreremo
il legame tra la sua coomologia, la coomologia del complementare M
dell'arrangiamento di
iperpiani ad esso associato, e la coomologia della fibra di Milnor di M.
Infine daremo i risultati fino ad ora noti su queste coomologie.

giovedi' - 11-03-2004 (11:00 - Sala Riunioni) : Salma Kuhlmann

Primes and Irreducibles in Integer Parts of Exponential Fields
argomento: Logica Matematica

venerdi' - 12-03-2004 (09:15 - Pisa) : Convegno

Representation of semidefinite positive functions
argomento: Geometria
abstract:
For the polynomial rings this is known as "The Hilbert 17th problem". We
want to focus on the same problem on more general spaces, in particular
algebras of differentiable functions. Research on this topics was developed
using both arguments from analysis in the phase space and from real and
complex analytic geometry, and we want to underline these relations. Some
survey talks are also scheduled to give the state of the art from several
points of view.


----------------------------------------------------------------------------
----

Tentative program


Friday, March 12.

 9.15-10.15     A.Prestel:    Sums of squares of polynomial functions.
10.30-11.30     J.-M.Bony:    Nonnegative functions as sums of squares:
                              the C^infinity and C^k case.
11.45-12.45     C.Andradas:   Sums of squares of analytic functions.

15.00-16.00     P.W.Michor:   To be annonced.
16.15-17.15     K.Schmuegden: To be confirmed.
17.45-18.45     L.Migliorini: Some analytic problems in Hodge's Theory of
                              singular varieties.

Saturday, March 13

 9.15-10.15     J.-M.Bony:    The Fefferman-Phong inequality.
10.30-11.30     J.Fernando:   Some advances about the 17 Hilbert problem
                              for global analytic functions.
11.45-12.45     D.Del Santo:  The Fefferman-Phong inequality in the
                              locally tempered Weyl calculus.

15.00-15.45     F.Pieroni:    Sums of squares in Quasi-analytic
                              Denjoy-Carlemann classes.
16.00-16.45     L.Pernazza:   Writing C^k functions as sums of squares of
                              C^h functions: examples and counterexamples.
17.15-18.15     A.Parmeggiani:A natural inequality for systems:
                              Sharp-Garding or Fefferman-Phong?

sabato - 13-03-2004 (09:15 - Pisa) : convegno

Representation of semidefinite positive functions
argomento: Geometria
abstract:

Saturday, March 13

 9.15-10.15     J.-M.Bony:    The Fefferman-Phong inequality.

10.30-11.30     J.Fernando:   Some advances about the 17 Hilbert problem for
global analytic functions.

11.45-12.45     D.Del Santo:  The Fefferman-Phong inequality in the locally
tempered Weyl calculus.

15.00-15.45     F.Pieroni:    Sums of squares in Quasi-analytic
Denjoy-Carlemann classes.

16.00-16.45 L.Pernazza: Writing C^k functions as sums of squares of C^h
functions: examples and counterexamples.

17.15-18.15     A.Parmeggiani:A natural inequality for systems:
Sharp-Garding or Fefferman-Phong?

martedi' - 16-03-2004 (15:00 - Sala Riunioni) : Andras I. Stipsicz
Ozsvath--Szabo invariants and contact structures
argomento:non specificato
abstract:
The study of tight contact structures on closed 3-manifolds turned out to be
a very effective way for understanding certain geometric properties of the
3-manifold at hand. In the lecture we show a way to
find such structures and prove their tightness in some particular cases. For
example, we show that the result of almost any rational surgery on a
positive torus knot admits a tight contact structure. Tightness will be
proved by applying contact invariants recently introduced by Ozsvath and
Szabo


Giulia Curciarello
Segreteria Didattica
tel: 050-2213219
e-mail curciare at dm.unipi.it

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