- Geometria_Pisa - Mailing list — Dipartimento di Matematica, UniPI

seminario Roman Sauer (KIT)
by Roberto Frigerio 25 May '15

25 May '15

Buongiorno, dopodomani mercoledi' 27 maggio avra' luogo in aula seminari, alle ore 16, un seminario di Roman Sauer (Karlsruhe Institute of Technology). Seguono titolo e abstract. Saluti, Roberto Title: Volume and homology growth Abstract: Consider a tower of finite coverings of a closed manifold. We usually assume that the fundamental group is residually finite and that the tower corresponds to a residual chain of the fundamental group. We then ask: How does the size of the k-th homology group grow as we go up in the tower? By size we mean the rank or the cardinality of the torsion subgroup. We connect the homology growth for aspherical Riemannian manifolds in the above sense to the volume of balls.

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assegni di ricerca a Roma
by Roberto Frigerio 24 May '15

24 May '15

Buongiorno, vi segnalo i seguenti assegni di ricerca banditi oressi l'Universita' di Roma Sapienza: http://www2.mat.uniroma1.it/sites/default/files/bando2015-5.pdf [www2.mat.uniroma1.it] n.5/2015 per il conferimento di n. 2 assegni biennali e 1 assegno annuale categoria A tip. II _ Matematica e sue applicazioni. SSD: tutti scadenza: 22 giugno 2015 Saluti, Roberto

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Fwd: avviso seminario di matematica dr. Junyan Cao (26.05.2015)
by Daniele Angella 20 May '15

20 May '15

(scusate per gli eventuali annunci multipli.. segnalo ai possibili interessati un seminario a Pisa martedi' 26 maggio. un saluto) ---------- Forwarded message ---------- From: Valeria Giuliani <valeria.giuliani(a)sns.it> Date: Wed, May 20, 2015 at 10:55 AM Subject: avviso seminario di matematica dr. Junyan Cao (26.05.2015) SEMINARIO DI MATEMATICA Martedì 26 maggio 2015 ore 14:30 Scuola Normale Superiore Pisa Aula Fermi Junyan Cao (Institut de Mathématiques de Jussieu – Université Paris 6) Terrà un seminario dal titolo: “ Kodaira dimension of algebraic fiber spaces over abelian varieties” Abstract: I will talk about a joint paper with Mihai Paun; our main result is that, for a fibration $p: X\rightarrow T$ from a projective manifold to a torus, the Kodaira dimension of $X$ is not less than the Kodaira dimension of the generic fiber. A main ingredient in our proof is a fine estimate about the weak positivity of the direct image of the relative pluri-canonical bundle. Tutti gli interessati sono invitati a partecipare. Classe di Scienze Matematiche e Naturali Valeria Giuliani Scuola Normale Superiore Servizio alla Didattica e Allievi tel. 050 509260 Piazza dei Cavalieri, 7 56126 Pisa E-mail: valeria.giuliani(a)sns.it E-mail: classi(a)sns.it

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seminario del 6/5
by Paolo Lisca 04 May '15

04 May '15

Buongiorno a tutti, vi ricordo del seminario di mercoledì prossimo 6 maggio, alle 16 in sala seminari. Trovate i dati qui sotto. P Lisca ------------------- Speaker: Ana Garcia Lecuona, Université d'Aix-Marseille. Titolo: Splice links and colored signatures Abstract: The splice of two links is an operation defined by Eisenbund and Neumann which generalizes several other operations on links, such as the connected sum, the cabling or the disjoint union. The precise definition will be given in the talk but the rough idea goes as follows: the splice of the links L’ and L'' along the components K' and K'' is the link (L' \ K') U (L''\ K'') obtained by identifying the exterior of K' with the exterior of K''. There has been much interest to understand the behavior of different link invariants under the splice operation (genus, fiberability, Conway polynomial, Heegaard-Floer homology among others) and the goal of this talk is to present a formula relating the colored signature of the splice of two oriented links to the colored signatures of its two constituent links. As an immediate consequence, we have that the conventional univariate Levine-Tristram signature of a splice depends, in general, on the colored (or multivariate) signatures of the summands. There is one case for which we do not have yet a closed formula. If time permits, we will discuss this case whose study leads to a generalization of Kojima's eta-function for links.This is a joint work, still in progress, with Alex Degtyarev and Vincent Florens.

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seminari mercoledì
by Bruno Martelli 13 Apr '15

13 Apr '15

buondì, segnalo due seminari per mercoledì prossimo, il nostro di geometria è anticipato alle 14.30. a presto, Bruno --- Wednesday, April 15, 2015 Ora Inizio: 14:30 Aula: Sala Seminari (Dip. Matematica) Relatore: Paolo Aceto (Università di Firenze) Titolo: Rational homology cobordisms of plumbed 3-manifolds and arborescent link concordance Abstract: We investigate rational homology cobordisms of 3-manifolds with non-zero first Betti number. This is motivated by the natural generalization of the slice-ribbon conjecture to multicomponent links. In particular we consider the problem of which rational homology S^1x S^2's bound rational homology S^1xD^3's. We give a simple procedure to construct rational homology cobordisms between plumbed 3-manifold. We introduce a family F of plumbed 3-manifolds with b_1=1. By adapting an obstruction based on Donaldson's diagonalization theorem we characterize all manifolds in F that bound rational homology S^1xD^3's. For all these manifolds a rational homology cobordism to S^1xS^2 can be constructed via our procedure. The family F is large enough to include all Seifert fibered spaces over the 2-sphere with vanishing Euler invariant. We also describe applications to arborescent link concordance. ---- Wednesday, April 15, 2015 Ora Inizio: 16:00 Aula: Sala Seminari (Dip. Matematica) Relatore: Alberto Abbondandolo (Univ. di Bochum e Univ. di Pisa) Titolo: How long is the shortest geodesic on a sphere?

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seminario domani
by Bruno Martelli 07 Apr '15

07 Apr '15

buondì, vi annuncio il seminario di geometria di domani, al quale siete tutti invitati. a presto, Bruno ---- Wednesday, April 8, 2015 Ora Inizio: 16:00 Aula: Sala Seminari (Dip. Matematica) SEMINARI DI GEOMETRIA Relatore: Antonio De Capua (University of Oxford) Titolo: Hyperbolic volume of links, via pants graphs and train tracks Abstract: A result of Jeffrey Brock states that, given a hyperbolic 3-manifold which is a mapping torus over a surface S, its volume can be expressed in terms of the distance induced by the monodromy map in the pants graph of S. This is an abstract graph whose vertices are pants decompositions of S, and edges correspond to some sort of 'elementary alterations' of those. Brock's theorem motivates investigation about distances in the pants graph; in particular we generalise a result of Masur, Mosher and Schleimer that train track splitting sequences (which will be defined during the talk) induce quasi-geodesics in the marking graph. This will be the core piece of a volume estimate for complements of closed braids in the solid torus.

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summer school "Cohomology and Large Scale Geometry"
by Roberto Frigerio 01 Apr '15

01 Apr '15

Buongiorno, vi segnalo la scuola estiva di cui nel subject, che si terra' a Regensburg dal 27 al 31 luglio. Qui potete trovarne una descrizione: http://clsg.sfb-higher-invariants.de Saluti, Roberto

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assegno di ricerca
by Bruno Martelli 20 Mar '15

20 Mar '15

Segnalo un assegno di ricerca dal PRIN di De Concini: http://www2.mat.uniroma1.it/node/5824 Bruno

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seminario oggi
by Bruno Martelli 18 Mar '15

18 Mar '15

puntualmente in ritardo, vi annuncio il seminario di geometria di oggi. a presto, Bruno ---- Wednesday, March 18, 2015 Ora Inizio: 16:00 Aula: Sala Seminari (Dip. Matematica) SEMINARI DI GEOMETRIA Viveca Erlandsson (Aalto University) Counting self-intersecting multicurves Abstract: I will describe some joint work in progress with Juan Souto studying the asymptotic growth on the number $n_k^S(L)$ of multicurves with $k$ self-intersections of length at most $L$ on a hyperbolic surface $S$. More concretely, I will show that for small $k$, $\frac{n_k^S(L)}{L^{6g-6}}$ has a limit as $L\to\infty$. Moreover, when $S$ is the punctured torus, this limit exists for any fixed $k$.

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A Complex Geometry Day in Pisa
by Daniele Angella 16 Mar '15

16 Mar '15

Dear all, we are happy to announce a 1-day meeting on Complex Geometry that will be held on Friday May 15th, 2015 at Centro di Ricerca Matematica "Ennio de Giorgi" in Pisa. The workshop consists in seminars by young researchers on Kähler and non-Kähler geometry and related topics, with the aim to share recent results and start new collaborations. Invited speakers include: - Giovanni Bazzoni (Universität Bielefeld); - Andrea Cattaneo (Università di Parma); - Eleonora Di Nezza (Imperial College London); - Riccardo Lena (Università di Parma); - Giulia Sarfatti (Università di Bologna); - Pietro Tortella. Anyone interested in the programme is welcome. A registration form, and more and updated informations, are available at the website: http://crm.sns.it/event/350/ . See also http://gecogedi.dimai.unifi.it/event/139/ . The event is supported by Centro di Ricerca Matematica "Ennio de Giorgi" and by Scuola Normale Superiore, as part of the SNS GR project "Geometry of non-Kähler manifolds". You are welcome to contact the organizers: - Daniele Angella - daniele.angella(a)gmail.com - Simone Calamai - simocala(a)gmail.com - Michela Zedda - michela.zedda(a)gmail.com

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