Geometria_Pisa April 2024

geometria_pisa@lists.dm.unipi.it

4 participants
7 discussions

Fwd: Postdoc position at Università di Firenze
by Bruno Martelli 24 Apr '24

24 Apr '24

---------- Forwarded message --------- Da: Daniele Angella <daniele.angella(a)unifi.it> Date: Mer 24 Apr 2024, 08:10 Subject: Postdoc position at Università di Firenze To: geometriaglobale-group(a)unifi.it <geometriaglobale-group(a)unifi.it>, dimai-geometria-group(a)unifi.it <dimai-geometria-group(a)unifi.it>, GEOMETRY(a)listserv.utk.edu <GEOMETRY(a)listserv.utk.edu>, EAGER-GEN(a)listserv.dfn.de <EAGER-GEN(a)listserv.dfn.de> Dear all, We are looking for candidates for a Postdoc position at Università di Firenze, Italy, starting from September 2024. The position is funded by the PRIN2022 Project "Real and Complex Manifolds: Geometry and holomorphic dynamics". The call is open until the deadline June 20th, 2024: https://titulus.unifi.it/albo/viewer?view=files%2F005484724-UNFICLE-93897a4… Please forward the announcement to potential candidates! All the best, daniele

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I: Seminario baby geometri
by Giovanni Framba 22 Apr '24

22 Apr '24

Dato che il seminario di geometria è stato annullato, condivido l'invito al seminario dei BabyGs. Vi aspettiamo, Giovanni ________________________________ Da: Giovanni Framba via Dottorandi <dottorandi(a)lists.dm.unipi.it> Inviato: lunedì 22 aprile 2024 21:32 A: Studenti <studenti(a)dm.unipi.it>; dottorandi(a)dm.unipi.it <dottorandi(a)dm.unipi.it>; babygs-users(a)googlegroups.com <babygs-users(a)googlegroups.com> Oggetto: [dottorato] Seminario baby geometri Carə tuttə, Il seminario dei baby geometri di questa settimana si terrà domani Martedì 23 Aprile alle 14.30 in Aula Riunioni. Manousos Manouras (Université de Pau / Universidad de Zaragoza) parlerà di "Alexander type invariants of line arrangements". Di seguito l'abstract. There have been various definitions of the Alexander invariants of a knot. Following some of these definitions one can generalise them so as to have coefficients twisted by a linear representation. The Alexander type invariants are known to detect non-trivial topological information(genus, hyperbolic volume of a knot etc). The twisted Alexander polynomial was introduced by Wada for knots and has been studied thereafter for more general manifolds as the complement of algebraic curves or line arrangements. We will discuss the relation of the twisted Alexander polynomial of the exterior manifold of a line arrangement and the twisted Alexander polynomial of its boundary manifold. We will present how using twisted Alexander polynomials induced by reducible representations, we can retract nontrivial topological information. We will also deal with the characteristic varieties of line arrangements, studied by various authors such as Zariski, Libgober, Artal. The main problem is to understand if the characteristic varieties are combinatorially determined in general. This is known to be true for their ”homogeneous part”, which corresponds to the resonance variety, as well as for the translated components having dimension at least one, as they are determined by orbifold pencils. This does not work in the same way for the 0-dimensional translated components. Here we present examples such that the characteristic variety has some translated 0-dimensional global component. Ci troveremo alle 13 in atrio per andare a pranzo con lo speaker. Le informazioni sui prossimi seminari si trovano sul sito dei Baby Geometri! Vi aspettiamo! Buona serata, Filippo, Giovanni e Giuseppe

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Seminario di geometria 23/04
by Filippo Bianchi 22 Apr '24

22 Apr '24

Carə tuttə, Il seminario di geometria di questa settimana si terrà domani Martedì 23 Aprile alle 14.30 in Aula Riunioni. Isaac Sundberg (MPIM Bonn) parlerà di "Khovanov homology and surfaces in the 4-ball". Di seguito l'abstract. It is difficult to detect differences between topological and smooth phenomena, so it was surprising when Rasmussen used a purely combinatorial theory, known as Khovanov homology, to obstruct the smooth sliceness of topologically slice knots. In this talk, we discuss another application of this homology theory: obstructing smooth isotopy of topologically isotopic surfaces in the 4-ball. We highlight recent results and give an idea of the construction for this obstruction. Ci troveremo alle 13 in atrio per andare a pranzo con lə speaker. Le informazioni sui prossimi seminari si trovano sul sito<https://www.dm.unipi.it/en/seminars/?category=653b522f8f0af760bdc42729>. Vi aspettiamo! Buona serata, Filippo, Giovanni e Giuseppe

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Seminario di geometria 15/04
by Filippo Bianchi 14 Apr '24

14 Apr '24

Carə tuttə, Il seminario di geometria della prossima settimana si terrà eccezionalmente domani Lunedì 15 Aprile alle 11.00 in Aula Magna. Marco Golla (Université de Nantes) parlerà di "Line arrangements with only triple points". Di seguito l'abstract. Line arrangements are unions of lines in a (projective or affine) space over some field and they are studied from a combinatorial or algebro-geometrical standpoint. (Non-trivial) complex line arrangements always have at least a double or a triple point, a point where exactly two or three lines meet. Does there exist 13 lines in the complex projective plane that only meet at triple points? I will discuss some topological ideas around this question and higher-degree variants. Le informazioni sui prossimi seminari si trovano sul sito<https://www.dm.unipi.it/en/seminars/?category=653b522f8f0af760bdc42729>. Vi aspettiamo! Buona serata, Filippo, Giovanni e Giuseppe

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I: Conference in low-dimensional topology - Budapest 8th-12th July 2024
by Paolo Lisca 10 Apr '24

10 Apr '24

Inoltro annuncio di convegno di topologia in bassa dimensione. Paolo Lisca ________________________________ Da: marengon <marengon.marco(a)renyi.hu> Inviato: mercoledì 10 aprile 2024 01:18 A: New.Structures Low.Dimensional.Topology Oggetto: Conference in low-dimensional topology - Budapest 8th-12th July 2024 Dear colleague, We would like to advertise a conference in low-dimensional topology, organized by the Simons collaboration "New structures in low-dimensional topology", which will take place at the Rényi Institute in Budapest (Hungary) on the week of 8th-12th July 2024. The target audience of the summer school includes advanced graduate students, postdocs, and established researchers. See https://erdoscenter.renyi.hu/events/conference-new-structures-low-dimension… for more information. We have limited funding to support some junior participants as well as limited space. Registration and application for funding is now open at the above link. The deadline for application is 25th April 2024. Please forward this message to anyone who might be interested in applying. Our best wishes, The organizers

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Seminario di geometria 11/04
by Filippo Bianchi 09 Apr '24

09 Apr '24

Carə tuttə, Giovedì 11 Aprile alle 14.30 in Aula Seminari si terrà il seminario di Michael Brandenbursky (Ben Gurion University of the Negev) dal titolo "Invariant norms on diffeomorphism groups: old and new results". Di seguito l'abstract. Invariant norms appear in most branches of mathematics. Examples include word norms (autonomous, entropy, fragmentation) and non-discrete norms (Hofer norm) in symplectic geometry. In group theory examples include commutator length and primitive length. After providing some history and motivation, I will focus on a group G of volume-preserving diffeomorphisms of a compact smooth orientable manifold. In particular, I will discuss L^p-geometry of this group and which groups can be quasi-isometrically embedded in G. This talk is partially based on a joint work with M. Marcinkowski and E. Shelukhin. Le informazioni sui prossimi seminari si trovano sul sito<https://www.dm.unipi.it/en/seminars/?category=653b522f8f0af760bdc42729>. Come sempre, ci troveremo in atrio alle 13 per andare a pranzo con lo speaker. Vi aspettiamo! Buona giornata, Filippo, Giovanni e Giuseppe

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Seminario Paolo Ghiggini domani
by Bruno Martelli 03 Apr '24

03 Apr '24

Buongiorno, Con colpevole ritardo segnalo il seminario di geometria di domani (ore 14.30 aula seminari). A presto, Bruno ----- Orbite di Reeb e invarianti di varietà suturate Paolo Ghiggini Giovedì 4 apr 2024 - 14:30 Aula Seminari (Department of Mathematics) Le orbite chiuse del flusso di Reeb di una forma di contatto producono un invariante topologico di varietà di dimensione tre detto "omologia di contatto immersa" definito da Michael Hutchings circa vent'anni fa. In seguito la definizione è stata estesa alle varietà suturate (cioè con bordo decorato da una multicurva) da Vincent Colin, Ko Honda, Michael Hutchings e me. D'altra parte l'omologia di Heegaard Floer di Ozsváth e Szabó è stata estesa alle varietà suturate da András Juhász. Nel mio seminario spiegherò i punti chiave della dimostrazione che l'omologia di Heegaard Floer e l'omologia di contatto immersa di varietà suturate sono isomorfe. Questo risultato generalizza (e utilizza) l'isomorfismo tra l'omologia di Heegaard Floer e l'omologia di contatto immersa per varietà chiuse dimostrato anni or sono da Colin, Honda e me. Tutto quello che racconterò è stato ottenuto in collaborazione con Colin e Honda.

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Geometria_Pisa April 2024