- Notiziario - Mailing list — Dipartimento di Matematica, UniPI

[Settimanale] Rose
by Broglia 24 Jun '06

24 Jun '06

_______________________________________________ Settimanale mailing list Settimanale(a)mail.dm.unipi.it https://mail.dm.unipi.it/mailman/listinfo/settimanale

1 0

[Settimanale] Fw: Avviso Seminario di Matematica, prof. David W. MASSER (06.07.06)
by Giulia Curciarello 22 Jun '06

22 Jun '06

SEMINARIO DI MATEMATICA Giovedì 6 luglio 2006 ore 16.00 Scuola Normale Superiore Pisa (Aula Tonelli) David W. MASSER Università di Basilea Terrà un seminario dal titolo: "Linear equations in multiplicative groups over positive characteristic" Abstract The equation $a_1x_1+...+a_nx_n=1$, to be solved in unknowns $x_1,...,x_n$ lying in a fixed multiplicative group, has been much studied in the case of zero characteristic. However there are not many results over positive characteristic. This case is generally easier to handle, but it presents interesting new features. For example, although the equation can have infinite $(n-2)$-parameter families of solutions, these can be classified and estimated in a completely effective way. This has applications to multiple mixing problems for algebraic actions on disconnected compact abelian groups. Tutti gli interessati sono invitati a partecipare. La Segreteria della Classe di Scienze - - - - - Michele Verde Scuola Normale Superiore Segreteria Classe di Scienze Tel. 050-509048 Fax. 050-509045 Piazza Dei Cavalieri, 7 56126 Pisa E-Mail: m.verde(a)sns.it E-Mail: segreteria.scienze(a)sns.it - - - - - Le informazioni contenute nella presente e-mail e nei relativi allegati possono essere riservate e sono, comunque, destinate esclusivamente al destinatario in indirizzo. E' vietata, pertanto, la diffusione, distribuzione e/o copiatura di tali informazioni da parte di qualsiasi soggetto diverso dal destinatario. Chiunque abbia ricevuto o letto questa e-mail per errore o senza esserne legittimato è invitato a darne immediatamente notizia al mittente tramite fax o e-mail e a distruggerla. Grazie. _______________________________________________ Settimanale mailing list Settimanale(a)mail.dm.unipi.it https://mail.dm.unipi.it/mailman/listinfo/settimanale

1 0

[Utenti] [Settimanale] Seminario prof. Ruiz (fwd)
by Francesca Acquistapace 16 Jun '06

16 Jun '06

Prego notare l'ora Grazie Francesca Acquistapace mercoledi' 21-06-2006 Ore 15:00 PRECISE - Sala dei Seminari Jesus Ruiz (Universitad Complutense Madrid) : "Open questions concernings Hilbert's 17th Problem for analytic curves" Abstract The Hilbert 17th Problem asks when a psd function is a sum of squares, and of how many. For real analytic curves this reduces to the local problem for germs at singular points. For those germs, the problem splits into the consideration of their irreducible branches. Now, irreducible curve germs are classically discussed using the semigroup of values: all irreducible curves with fixed semigroup form a "moduli" algebraic set in some finite dimensional affine space. There, Pythagoras numbers, positive semidefinite germs, sum of squares provide semialgebraic mappings on and stratifications of the "moduli" set. The understanding od these semialgebraic data is a difficult matter that has surprising connections with classical concepts (for instance, Arf curves and Pythagorean curves are one and the same thing). ************************* Segreteria Didattica Giulia Curciarello tel- 050 2213219 ************************* _______________________________________________ Settimanale mailing list Settimanale(a)mail.dm.unipi.it https://mail.dm.unipi.it/mailman/listinfo/settimanale _______________________________________________ Utenti mailing list Utenti(a)mail.dm.unipi.it https://mail.dm.unipi.it/mailman/listinfo/utenti _______________________________________________ Settimanale mailing list Settimanale(a)mail.dm.unipi.it https://mail.dm.unipi.it/mailman/listinfo/settimanale

1 0

[Settimanale] SEMINARIO DI SISTEMI DINAMICI OLOMORFI (e dintorni)
by Giulia Curciarello 15 Jun '06

15 Jun '06

SEMINARIO DI SISTEMI DINAMICI OLOMORFI (e dintorni) Martedi' 20 giugno 2006 0re 14.30 Sala Conferenze Collegio Puteano Corinna ULCIGRAI (Princeton) "Mixing for flows over interval exchange transformations" Abstract: We consider suspension flows over interval exchange transformations, under a roof function with logarithmic singularities. Such flows arise as minimal components of flows on surfaces given by multi-valued Hamiltonians. We prove that if the roof function has an asymmetric logarithmic singularity, the suspension flow is strongly mixing for a full measure set of interval exchanges. This generalizes a result by Khanin and Sinai for flows over rotations of the circle. In the proof we use a recent result by Avila-Gouzel-Yoccoz. ************************* Segreteria Didattica Giulia Curciarello tel- 050 2213219 ************************* _______________________________________________ Settimanale mailing list Settimanale(a)mail.dm.unipi.it https://mail.dm.unipi.it/mailman/listinfo/settimanale

1 0

[Settimanale] Fw: Colloquio De Giorgi, Prof. Lucien SZPIRO (21.06.06)
by Giulia Curciarello 15 Jun '06

15 Jun '06

COLLOQUIO DE GIORGI Lucien SZPIRO Graduate Center CUNY NewYork "Algebraic Dynamics" Abstract Preperiodic points over number fields and function fields, Equidistribution of small points, Critical bad reduction and a Shafarevich-Faltings finitness theorem for dynamics on the projective line. Mercoledì 21 giugno 2006 ore 17.00 Aula Mancini Piazza dei Cavalieri,7 PISA _______________________________________________ Settimanale mailing list Settimanale(a)mail.dm.unipi.it https://mail.dm.unipi.it/mailman/listinfo/settimanale

1 0

[Settimanale] Fw: Nicolai Krylov, "On the maximum principle for SPDEs..."
by Giulia Curciarello 14 Jun '06

14 Jun '06

> CENTRO DI RICERCA MATEMATICA ENNIO DE GIORGI > > Nell'ambito del semestre su "Analisi Stocastica" in corso di svolgimento > presso il Centro De Giorgi, il Prof. NICOLAI KRYLOV (University of > Minnesota) terra' due lezioni su: > > "On the maximum principle for SPDEs, the continuity of their solutions, > and the law of square root for Brownian motion" > > ABSTRACT: > The maximum principle for SPDEs is established in multidimensional > $C^{1}$ domains. An application is given to proving the Hoelder > continuity up to the boundary of solutions of one-dimensional SPDEs. A > new law of square root for Brownian motion, discovered in connection > with the continuity, plays a crucial role. > > Le lezioni si terranno in Sala Conferenze (Collegio Puteano, Piazza dei > Cavalieri 3 Pisa) secondo il seguente calendario: > > Mercoledi' 21 Giugno, 10.30-12.30 > Giovedi' 22 Giugno, 10.30-12.30 > > Tutti gli interessati sono invitati a partecipare. _______________________________________________ Settimanale mailing list Settimanale(a)mail.dm.unipi.it https://mail.dm.unipi.it/mailman/listinfo/settimanale

1 0

[Settimanale] Seminario prof. Ruiz
by Giulia Curciarello 13 Jun '06

13 Jun '06

mercoledi' 21-06-2006 (15:00) - Sala dei Seminari Jesus Ruiz (Universitad Complutense Madrid) : Open questions concernings Hilbert's 17th Problem for analytic curves Abstract The Hilbert 17th Problem asks when a psd function is a sum of squares, and of how many. For real analytic curves this reduces to the local problem for germs at singular points. For those germs, the problem splits into the consideration of their irreducible branches. Now, irreducible curve germs are classically discussed using the semigroup of values: all irreducible curves with fixed semigroup form a "moduli" algebraic set in some finite dimensional affine space. There, Pythagoras numbers, positive semidefinite germs, sum of squares provide semialgebraic mappings on and stratifications of the "moduli" set. The understanding od these semialgebraic data is a difficult matter that has surprising connections with classical concepts (for instance, Arf curves and Pythagorean curves are one and the same thing). ************************* Segreteria Didattica Giulia Curciarello tel- 050 2213219 ************************* _______________________________________________ Settimanale mailing list Settimanale(a)mail.dm.unipi.it https://mail.dm.unipi.it/mailman/listinfo/settimanale

1 0

[Settimanale] SEMINARIO DI SISTEMI DINAMICI OLOMORFI (e dintorni)
by Giulia Curciarello 09 Jun '06

09 Jun '06

SEMINARIO DI SISTEMI DINAMICI OLOMORFI (e dintorni) Martedi' 20 giugno 2006 Sala Conferenze Collegio Puteano > > Corinna ULCIGRAI (Princeton) > ulcigrai(a)math.princeton.edu > "Mixing for flows over interval exchange transformations" > > Abstract: We consider suspension flows over interval > exchange transformations, > under a roof function with logarithmic singularities. Such > flows arise as minimal > components of flows on surfaces given by multi-valued > Hamiltonians. We prove > that if the roof function has an asymmetric logarithmic > singularity, the suspension > flow is strongly mixing for a full measure set of interval > exchanges. This generalizes > a result by Khanin and Sinai for flows over rotations of > the circle. > In the proof we use a recent result by > Avila-Gouzel-Yoccoz. _______________________________________________ Settimanale mailing list Settimanale(a)mail.dm.unipi.it https://mail.dm.unipi.it/mailman/listinfo/settimanale

1 0

[Settimanale] Fw: SNS Cattedra Galileiana 2006 - Yakov G. SINAI
by Giulia Curciarello 08 Jun '06

08 Jun '06

Si trasmette in allegato l'annuncio relativo alla Cattedra Galileiana che avra' inizio lunedi' 12 giugno presso la Scuola Normale. Chi fosse interessato a partecipare e' pregato di restituire il modulo incluso nel pieghevole all'Associazione Amici per fax al no. 050-509179 oppure di inviare un messaggio di posta elettronica con i dati richiesti a amicisns(a)sns.it . Le informazioni contenute nella presente e-mail e nei relativi allegati possono essere riservate e sono, comunque, destinate esclusivamente al destinatario in indirizzo. E' vietata, pertanto, la diffusione, distribuzione e/o copiatura di tali informazioni da parte di qualsiasi soggetto diverso dal destinatario. Chiunque abbia ricevuto o letto questa e-mail per errore o senza esserne legittimato è invitato a darne immediatamente notizia al mittente tramite fax o e-mail e a distruggerla. Grazie. _______________________________________________ Settimanale mailing list Settimanale(a)mail.dm.unipi.it https://mail.dm.unipi.it/mailman/listinfo/settimanale

1 0

[Settimanale] Avvisi di Seminari
by Giulia Curciarello 08 Jun '06

08 Jun '06

I seminari inizieranno alle 15 e proseguiranno con il seguente programma martedi' 13-06-2006 (15:00) - l'Aula Magna del Dipartimento di Matematica "L. Tonelli" Giandomenico Orlandi : One day miniworkshop on Variational Problems:Dynamics of Ginzburg-Landau vortices and critical points of the Kirchhoff functional. Abstract: For the two dimensional complex parabolic Ginzburg-Landau equation we prove that, asymptotically, vortices evolve according to a simple ordinary differential equation, which is a gradient flow of the Kirchhoff-Onsager functional. This convergence holds except for a finite number of times, corresponding to vortex collisions and splittings, which we describe carefully. The only assumption is a natural energy bound on the initial data. martedi' 13-06-2006 (16:00) - l'Aula Magna del Dipartimento Cyrill Muratov : "One day miniworkshop on Variational Problems". A Variational Approach to Front Propagation in Infinite Cylinders. Abstract: Gradient reaction-diffusion-advection systems arise in the context of modeling the kinetics of phase transitions, population dynamics and combustion. These systems are known to exhibit a variety of non-trivial spatio-temporal behaviors, most notably the phenomenon of propagation and traveling waves. We introduce a variational formulation for the traveling wave solutions in cylindrical geometries with transverse potential flow, which allows us to construct a certain class of traveling wave solutions and establish their monotonicity, asymptotic decay and, under some extra assumptions, uniqueness. These solutions are special in a sense that they are characterized by a non-generic fast exponential decay ahead of the wave and play an important role in propagation phenomena for the initial value problem. We also construct an area-type functional that gives a matching upper and lower bound for the propagation speed in the sharp reaction zone limit for weakly curved fronts. ore 17.00 coffe-break martedi' 13-06-2006 (17:30) - l'Aula Magna del Dipartimento "L. Tonelli" Dorin Bucur : "One day miniworkshop on Variational Problems". Shape analysis of the crack inverse problem Abstract: The talk deals with the identifiability of non-smooth defects by boundary measurements, and the stability of their detection. We extend the result of Alessandrini and Valenzuela on the unique determination of a finite number of cracks or cavities by two boundary measurements, to arbitrary closed sets satisfying quasi-everywhere a {\it conductivity assumption}. This new regularity concept is to be compared to the Wiener criterion, rather than to the usual smoothness of the boundary. Relying on the geometric stability of the direct problem, we discuss the stability of the inverse problem without imposing any a priori boundary regularity of the unknown defects. As an application, we give a rigorous justification of the finite elements approximation of the defects. ***************************************************************** lunedi' 19-06-2006 (11:00) - Sala riunioni Irinel Dragan (Dept. of Mathematics, Univ.of Texas at Arlington, USA) : seminari congiunti col DIPART.MATEMATICA APPLICATA: On the Semivalues and the Shapley value for cooperative transferable utility games ******************************************************************* mercoledi' 21-06-2006 (15:00) - Sala dei Seminari Jesus Ruiz (Universitad Complutense Madrid) : Open questions concernings Hilbert's 17th Problem for analytic curves Abstract The Hilbert 17th Problem asks when a psd function is a sum of squares, and of how many. For real analytic curves this reduces to the local problem for germs at singular points. For those germs, the problem splits into the consideration of their irreducible branches. Now, irreducible curve germs are classically discussed using the semigroup of values: all irreducible curves with fixed semigroup form a "moduli" algebraic set in some finite dimensional affine space. There, Pythagoras numbers, positive semidefinite germs, sum of squares provide semialgebraic mappings on and stratifications of the "moduli" set. The understanding od these semialgebraic data is a difficult matter that has surprising connections with classical concepts (for instance, Arf curves and Pythagorean curves are one and the same thing). ******************************* ************************* Segreteria Didattica Giulia Curciarello tel- 050 2213219 ************************* _______________________________________________ Settimanale mailing list Settimanale(a)mail.dm.unipi.it https://mail.dm.unipi.it/mailman/listinfo/settimanale

1 0