Geometria_Pisa

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763 discussions

[Indico] Vijaylaxmi Trivedi, Hilbert-Kunz density function and its applications to some Hilbert-Kunz multiplicity conjectures, 26/10/2022, 16:30 Europe/Rome
by francesco.sala＠unipi.it 24 Oct '22

24 Oct '22

Title: Hilbert-Kunz density function and its applications to some Hilbert-Kunz multiplicity conjectures, Speaker(s): Vijaylaxmi Trivedi, Tata Institute of Fundamental Research, India, Date and time: 26 Oct 2022, 16:30 (Europe/Rome), Lecture series: Algebraic and Arithmetic Geometry Seminar, Venue: Scuola Normale Superiore, Pisa (Aula Mancini). You can access the full event here: https://events.dm.unipi.it/e/106 Abstract -------- In this talk we introduce a compactly supported and real valued continuous function called Hilbert-Kunz (HK) density function. We briefly describe its properties and its applications to study characteristic p-invariants like HK multiplicity and F -thresholds.Further we discuss in more detail some long standing conjectures of Watanabe-Yoshida and Yoshida on the HK multiplicities of quadric hypersurfaces.Here, using the classification of ACM bundles on the smooth quadric via matrix factorizations, we describe the HK density functions of the quadrics. The structure of the function explains the difficulties in nailing down the computations of HK multiplicities of even such simple class of rings.As a corollary we prove a part of the Watanabe-Yoshida conjecture for all dimensions. Moreover, for large p, we give a closed formula for HK multiplicities of quadrics hypersurfaces and a proof of Yoshida’s conjecture. -- Indico :: Email Notifier https://events.dm.unipi.it/e/106

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[Indico] Vasudevan Srinivas, On finite presentation for the tame fundamental group, 26/10/2022, 15:00 Europe/Rome
by francesco.sala＠unipi.it 24 Oct '22

24 Oct '22

Title: On finite presentation for the tame fundamental group, Speaker(s): Vasudevan Srinivas, Tata Institute of Fundamental Research, India, Date and time: 26 Oct 2022, 15:00 (Europe/Rome), Lecture series: Algebraic and Arithmetic Geometry Seminar, Venue: Scuola Normale Superiore, Pisa (Aula Mancini). You can access the full event here: https://events.dm.unipi.it/e/105 Abstract -------- This is a report on joint work with H. Esnault and M. Schusterman.Recall that the étale fundamental group of a variety over an algebraically closed field of characteristic 0 is known to be a finitely presented profinite group; this is proved by first reducing to varieties over the complex numbers, and then comparing with the topological fundamental group. In positive characteristics, even if we restrict to smooth varieties, finite generation fails in general for étale fundamental groups of non-proper varieties (eg, for the affine line).For a smooth variety with a smooth, projective compactification with an SNC boundary divisor, we show that the tame fundamental group is a finitely presented profinite group. In particular, this holds for the étale fundamental groups of smooth projective varieties. -- Indico :: Email Notifier https://events.dm.unipi.it/e/105

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[Indico] Andrea Ricolfi, TBA, 23/11/2022, 15:00 Europe/Rome
by francesco.sala＠unipi.it 21 Oct '22

21 Oct '22

Title: TBA, Speaker(s): Andrea Ricolfi, SISSA, Trieste, Date and time: 23 Nov 2022, 15:00 (Europe/Rome), Lecture series: Algebraic and Arithmetic Geometry Seminar, Venue: Department of Mathematics (Aula Magna). You can access the full event here: https://events.dm.unipi.it/e/116 -- Indico :: Email Notifier https://events.dm.unipi.it/e/116

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[Indico] Michael Wemyss, Hyperplane arrangements, monodromy via deformation theory, and stability conditions, 20/10/2022, 16:00 Europe/Rome
by francesco.sala＠unipi.it 19 Oct '22

19 Oct '22

Title: Hyperplane arrangements, monodromy via deformation theory, and stability conditions, Speaker(s): Michael Wemyss, University of Glasgow, Date and time: 20 Oct 2022, 16:00 (Europe/Rome), Lecture series: Seminar on Combinatorics, Lie Theory, and Topology, Venue: Department of Mathematics (Aula Magna). You can access the full event here: https://events.dm.unipi.it/e/31 Abstract -------- The infinite hyperplane arrangements associated to affine Dynkin diagrams (and their associated braid groups) are fundamental throughout mathematics. I will explain a variation on this, which allows us to produce many more arrangements. Whilst these new arrangements need not be Coxeter, they are still "labelled" by Coxeter data. The motivation comes from algebraic geometry. In that setting, monodromy around these hyperplanes corresponds to certain symmetries, which are realised using (noncommutative) deformation theory of curves. The hyperplanes turn out to control the Bridgeland stability manifold, and this in turn relates to open questions around the $K(\pi,1)$-conjecture. This is summary of joint work with Donovan, Iyama, and Hirano. -- Indico :: Email Notifier https://events.dm.unipi.it/e/31

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[Indico] Ádám Gyenge, The Heisenberg category of a category, 19/10/2022, 15:00 Europe/Rome
by francesco.sala＠unipi.it 17 Oct '22

17 Oct '22

Title: The Heisenberg category of a category, Speaker(s): Ádám Gyenge, Alfréd Rényi Institute of Mathematics, Date and time: 19 Oct 2022, 15:00 (Europe/Rome), Lecture series: Algebraic and Arithmetic Geometry Seminar, Venue: Department of Mathematics (Aula Magna). You can access the full event here: https://events.dm.unipi.it/e/111 Abstract -------- The Heisenberg algebra associated with a lattice is a much-investigated object originating in quantum theory. Khovanov introducedrecently a categorification of the infinite Heisenberg algebraassociated with the free boson or, equivalently, a rank 1 lattice,using a graphical construction involving planar diagrams. We extendKhovanov’s graphical construction to derived categories of smooth andprojective varieties or, more generally, to categories having a Serrefunctor. In our case, the underlying lattice will be the (numerical)Grothendieck group of the category. We also obtain a 2-representationof our Heisenberg category on a categorical analogue of the Fockspace. Joint work with Clemens Koppensteiner and Timothy Logvinenko. -- Indico :: Email Notifier https://events.dm.unipi.it/e/111

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[Indico] Michael Wemyss, Hyperplane arrangements, monodromy via deformation theory, and stability conditions, 20/10/2022, 16:00 Europe/Rome
by francesco.sala＠unipi.it 14 Oct '22

14 Oct '22

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Fwd: Colloquio di Matematica del Dini
by Marco Abate 08 Oct '22

08 Oct '22

Carissimi, vi giro questo annuncio di seminario a Firenze. Ciao, Marco > > > ---------- Forwarded message --------- > From: Daniele Angella <daniele.angella(a)unifi.it> > Date: Mon, Oct 3, 2022 at 2:43 PM > Subject: Colloquio di Matematica del Dini > To: <dimai-news-group(a)unifi.it>, <dimai-dottorandi-group(a)unifi.it>, > <dimai-seminari-group(a)unifi.it> > Cc: Matteo Focardi <matteo.focardi(a)unifi.it>, Eugenio Giannelli > <eugenio.giannelli(a)unifi.it> > > > Carissime/i, > > il secondo "Colloquio di Matematica del Dini" sarà venerdì 28 ottobre, > in aula 202 del DiMaI, alle ore 14:30, tenuta dalla Prof.ssa Claire > Voisin (Institut de Mathématiques de Jussieu): > > On the topology of hyper-Kähler manifolds > > Abstract: Hyper-Kähler manifolds are symplectic holomorphic compact > Kähler manifolds, a particular class of complex manifolds with trivial > canonical bundle. They form a very restricted class, both from the > Riemannian and complex geometry viewpoints. They also satisfy strong > topological restrictions that I will describe, and that follow from > the study of their deformations. I will also explain further > restrictions in dimension $4$, and a classification result obtained in > collaboration with Debarre, Huybrechts and Macrì. > > > Siete tutte/i pregate/i di pubblicizzare l'iniziativa fra gli studenti > e le studentesse, esortandoli a partecipare (riceveranno comunque a > breve una mail in merito). > > In allegato trovate la locandina dell'evento. > > > Cari saluti, > > Daniele, Eugenio, Matteo Prorettore per la Didattica Università di Pisa ********************************************************** Marco Abate Tel: +39/050/2213.230 Dipartimento di Matematica Fax: +39/050/2210.678 Universita' di Pisa Largo Pontecorvo 5 E-mail: marco.abate(a)unipi.it 56127 Pisa Italy Web: pagine.dm.unipi.it/abate/ **********************************************************

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[Indico] Lorenzo Venturello, Flag spheres and $\gamma$-positivity, 06/10/2022, 16:00 Europe/Rome
by francesco.sala＠unipi.it 05 Oct '22

05 Oct '22

Title: Flag spheres and $\gamma$-positivity, Speaker(s): Lorenzo Venturello, Università di Pisa, Date and time: 6 Oct 2022, 16:00 (Europe/Rome), Lecture series: Seminar on Combinatorics, Lie Theory, and Topology, Venue: Department of Mathematics (Aula Magna). You can access the full event here: https://events.dm.unipi.it/e/107 Abstract -------- The $f$-vector of a simplicial complex is the vector whose entries record the number of faces in each dimension. It is typically convenient to study an integer linear transformation of the $f$-vector, called the $h$-vector, which naturally appears in the Hilbert series of an algebra associated to the simplicial complex. When we impose additional topological or combinatorial property on the complex, we observe linear relations or inequalities among the entries of the $h$-vector. For instance, when the complex triangulates a sphere, the $h$-vector is nonnegative, palindromic and unimodal. In this talk I will focus on a special family of triangulated spheres called flag and I will introduce a conjecture due to Gal which predicts precise linear inequalities which are stronger then thos ein the case of arbitrary spheres. Gal's inequalites can be conveniently encoded as statements of nonnegativity of a third integer vector, called $\gamma$-vector. I will show that a natural algebraic generalization of this conjecture does not hold (joint work with Alessio D'Alì) and comment on a reduction strategy proposed by Chudnowsky and Nevo (joint work in progress with Geva Yashfe). Finally, if time permits, I will present recent progress on a different $\gamma$-positivity problem involving triangulations of symmetric edge polytopes of a graph (joint work with Alessio D'Alì, Martina Juhnke-Kubitzke and Daniel Köhne). -- Indico :: Email Notifier https://events.dm.unipi.it/e/107

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Seminari Baby Geometri
by Giovanni Italiano 03 Oct '22

03 Oct '22

Cari tutti, care tutte, Vi scriviamo per informarvi che anche quest’anno organizziamo i seminari del Baby Geometri, un ciclo di seminari che ha lo scopo di approfondire argomenti classici o tematiche di ricerca nell'ambito della Geometria e della Topologia. I nostri seminari sono rivolti principalmente a studenti della magistrale e del dottorato (ma sono aperti a chiunque più in generale a chiunque sia interessato agli argomenti), conterranno una parte introduttiva apprezzabile da tutti e non saranno mai eccessivamente tecnici. I seminari si terranno in presenza, nelle aule del Dipartimento di Matematica o della Normale (variabile di settimana in settimana, a seconda della situazione), generalmente il martedì alle 14:30. Per il momento prevediamo anche di continuare a trasmetterli anche online via Microsoft Teams. Il primo seminario si terrà domani (martedì 4 ottobre) alle 14:30 in Aula Seminari (DM): Jeronimo Garcia Mejia (Karlsruher Institut für Technologie) The geometry of the Word Problem We will review a classical problem in group theory, the so-called Word Problem, from a geometric perspective by relating it to an even older geometric problem, the Isoperimetric Problem. The main actor being Dehn functions. We will talk about an interesting class of groups and review what is known about their Dehn functions and present some recent progress. If time allows it we will discuss the ideas behind it which will serve as an excuse to talk about an interesting open problem. Vi lascio un breve elenco degli speaker successivi, e ne approfitto per ricordarvi che potete sempre consultare il nostro sito http://people.dm.unipi.it/babygeometri/ per avere un programma aggiornato. venerdì 14 ottobre (online) - Oğuz Şavk (Stanford University / Boğaziçi University) martedì 18 ottobre - Laura Marino (Institut de Mathématiques de Jussieu) martedì 25 ottobre - Andrea Tamburelli (Università di Pisa) Nel caso desideriate essere aggiunti ad una mailing list con i reminder settimanali, potete rispondere a questa mail e vi aggiungeremo. A presto, Giuseppe Bargagnati Filippo Bianchi Giovanni Italiano Alice Merz Diego Santoro

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[Indico] Sam DeHority, Hecke correspondences and Lagrangian fibrations, 05/10/2022, 15:00 Europe/Rome
by francesco.sala＠unipi.it 03 Oct '22

03 Oct '22

Title: Hecke correspondences and Lagrangian fibrations, Speaker(s): Sam DeHority, Columbia University, Date and time: 5 Oct 2022, 15:00 (Europe/Rome), Lecture series: Algebraic and Arithmetic Geometry Seminar, Venue: Department of Mathematics (Aula Magna). You can access the full event here: https://events.dm.unipi.it/e/104 Abstract -------- I will discuss a method to associate new algebraic structures with deformations to certain holomorphic Lagrangian fibrations, and describe their relation with other parts of mathematical physics. This algebraic structure controls the enumerative geometry of the variety admitting the Lagrangian fibration in a way analogous to how a quantum group controls the enumerative geometry of a symplectic singularity. Various questions, including the monodromy of the quantum differential equation, can be answered using local-to-global techniques. -- Indico :: Email Notifier https://events.dm.unipi.it/e/104

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