Buongiorno,
Segnalo due seminari di geometria / algebra per domani pomeriggio.
A presto,
Bruno
======================================
giovedi` 31 maggio ore 15 aula seminari
Luca Battistella
Relative quasimaps and quasimap quantum Lefschetz
Quasimaps provide a compactification of the space of maps from smooth
curves to a GIT quotient; Ciocan-Fontanine and Kim used them to prove
beautiful wall-crossing formulae, comparing the resulting invariants with
ordinary Gromov-Witten ones. In joint work with Navid Nabijou, we introduce
the notion of genus zero relative quasimaps to a toric target X with
respect to a smooth (but not necessarily toric) hyperplane section Y,
extending work of Gathmann to this setting. Increasing the tangency
requirement gives us smaller and smaller moduli spaces; their virtual
classes are related by a simple recursion formula. Gathmann's inductive
algorithm allows us to compute restricted invariants of Y from those of X.
Under some positivity assumption, this can be made into a compact formula
for generating series of quasimap invariants, which recovers a result of
Ciocan-Fontanine and Kim. We are working towards an extension of this
approach to reduced genus one invariants.
giovedi` 31 maggio ore 16 aula seminari
Giovanni Inchiostro
Moduli of Weierstrass fibrations.
We study the the moduli space of KSBA stable pairs (X,sS+\sum a_i F_i),
consisting of a Weierstrass fibration X, its section S, and some fibers
F_i. We find a compactification which is a DM stack, and we prove that
there are wall-crossing morphisms when the weights s and a_i change. This
recovers the work of Ascher and Bejleri in the case in which s=1 and the
one of La Nave when s=1 and a_i=0.
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Cari tutti,
vi segnalo l'ultima attività per il ciclo di seminari dei Baby Geometri di
quest'anno:
Lunedì 28 Maggio alle 16:30
presso l'Aula Magna del Dipartimento di Matematica
Mauro Artigiani (Centro De Giorgi)
terrà un seminario dal titolo:
Dynamics on translation surfaces: a (very very very) short survey
di cui riporto l'abstract:
"Translation surfaces are surfaces which come naturally into play both
from a dynamical motivation (billiards in polygons) and from a more
algebro-geometrical point of view (they are related to the Teichmuller
space). We will start with some examples, give some motivations about why
one is interested in them and then focus more on the dynamical side. We
will give a short survey of some more or less classical result from the
very rich literature. Time permitting, we will also relate this to some
Diophantine approximation."
A seguire ci sarà un brindisi per sancire la fine del ciclo di seminari
per quest'anno!
Tutti gli interessati sono invitati a partecipare.
Per saperne di più sui prossimi seminari scrivete a
babygeometri(a)cs.dm.unipi.it
<https://student-web1.dm.unipi.it/squirrelmail/src/compose.php?send_to=babyg…>
o consultate la nostra pagina web:
http://people.dm.unipi.it/babygeometri/
Saluti,
Giulio Belletti, Edoardo Fossati e Marco Moraschini
Cari tutti,
vi segnalo questa attività per il ciclo di seminari dei Baby Geometri:
Venerdì 25 Maggio alle 16:30
presso l'Aula Seminari del Dipartimento di Matematica
Maylis Limouzineau (Università di Colonia)
terrà un seminario dal titolo:
Legendrian cobordisms
di cui riporto l'abstract:
Our framework here is low dimensional topology, and the main protagonists
are Legendrian submanifolds, i.e. those which remains obediently tangent
to the contact hyperplane distribution. We will see the subtleties brought
by Legendrian knots in comparison with classical smooth knots, and
understand the natural cobordism notion coming out, initiated by Arnol'd
in the early 80's:
"What is a Legendrian surface between two Legendrian knots?"
There will be infinitely many trivial knots, some bow ties, one swallow
tail... and a lot of drawings.
Tutti gli interessati sono invitati a partecipare.
Per saperne di più sui prossimi seminari scrivete a
babygeometri(a)cs.dm.unipi.it
<https://student-web1.dm.unipi.it/squirrelmail/src/compose.php?send_to=babyg…>
o consultate la nostra pagina web:
http://people.dm.unipi.it/babygeometri/
Saluti,
Giulio Belletti, Edoardo Fossati e Marco Moraschini
Dear colleague,
A Junior Research Fellow position (Ricercatore di Tipo A) is currently open
in algebra or geometry at the Math Department in Pisa.
Contract duration: 3 years
Gross annual salary: € 34.898
Deadline for application: 04/06/2018, 1 p.m.
Here is the link:
https://www.unipi.it/ateneo/bandi/ricercat/ricercator/Procedura-2/index.htm
I would be grateful if you could forward this information to any
potentially interested candidate.
Best wishes,
Bruno Martelli
Buongiorno,
Siete invitati al seminario di geometria di domani (c'è purtroppo una
sovrapposizione con un altro seminario in Normale di cui mi accorgo solo
ora... ).
A presto,
Bruno Martelli
16-May-2018 - 15:30
Sala Seminari (Dip. Matematica)
<http://www.dm.unipi.it/webnew/it/aula/sala-seminari-dip-matematica>
Pretzel links, mutation, and the slice-ribbon conjecture
<http://www.dm.unipi.it/webnew/it/seminari/pretzel-links-mutation-and-slice-…>
Paolo Aceto
We show that the mutant 2-component pretzel links P(p,q,-q,-p) and
P(p,q,-p,-q) are not concordant for any distinct odd integers p and q
greater than 1. As a corollary, we obtain a proof of the slice-ribbon
conjecture for 4-stranded 2-component pretzel links. In order to
distinguish mutant links up to concordance we consider 3-fold branched
covers and use an obstruction based on Donaldson's diagonalization theorem.
This is joint work with Min Hoon Kim, JungHwan Park and Arunima Ray.
Cari tutti,
vi segnalo questa attività per il ciclo di seminari dei Baby Geometri:
Lunedì 14 Maggio alle 16:30
presso l'Aula Seminari del Dipartimento di Matematica
Lorenzo Ruffoni (Università di Bologna)
terrà un seminario dal titolo:
Complex projective structures and Hilbert's XXI problem
di cui riporto l'abstract:
Complex projective structures are geometric structures locally modeled on
the geometry of the Riemann sphere with its group of Möbius
transformations PSL(2,C). As this space appears as a natural boundary at
infinity for the hyperbolic space, a typical feature of these structures
is the interplay between complex analysis and hyperbolic geometry, which
gives rise to a rich deformation theory. After reviewing some of the main
properties of their deformation space, we will discuss how the study of
complex projective structures can provide solutions to Hilbert's XXI
problem about monodromy groups of certain classes of ODEs on Riemann
surfaces.
Tutti gli interessati sono invitati a partecipare.
Per saperne di più sui prossimi seminari scrivete a
babygeometri(a)cs.dm.unipi.it
<https://student-web1.dm.unipi.it/squirrelmail/src/compose.php?send_to=babyg…>
o consultate la nostra pagina web:
http://people.dm.unipi.it/babygeometri/
Saluti,
Giulio Belletti, Edoardo Fossati e Marco Moraschini
Buondì,
Segnalo due seminari di geometria, oggi e domani (in due luoghi diversi).
A presto,
Bruno
-----
08-May-2018 - 15:00
Sala Conferenze (Puteano, Centro De Giorgi)
<http://www.dm.unipi.it/webnew/it/aula/sala-conferenze-puteano-centro-de-gio…>
Non-tangential convergence (and applications to holomorphic dynamics)
<http://www.dm.unipi.it/webnew/it/seminari/non-tangential-convergence-and-ap…>
Filippo Bracci
The notion of non-tangential convergence is one of the basic concept of
complex geoemtry in one and several variables. It is known that univalent
maps from the disc into the complex plane admit non-tangential limit almost
everywhere on the boundary of the disc, and Carathéodory’s prime ends
theory fully describe the boundary behavior. However, starting with a
simply connected domain, it is not clear in general when a given sequence
in that domain converges non-tangentially to the boundary of the disc after
pulling back via a Riemann map of the domain. The aim of this talk is to
give a complete answer to such a question in terms of hyperbolic geometry,
using Gromov’s hyperbolicity theory. Since every holomorphic self-map of
the unit disc has a (essentially unique) holomorphic linearizing model
(where dynamical properties of the map can be read via the geometry of the
model domain), the previous characterization allows to study the type of
convergence to the Denjoy-Wolff point for maps without inner fixed points.
In this talk we will restrict ourselves mainly to the case of semigroups of
holomorphic self-maps of the unit disc and show how to construct
“pathological” examples of semigroups whose orbits converge to the
Denjoy-Wolff point oscillating but non-tangentially, or partially
tangential and partially non-tangentially.
09-May-2018 - 15:30
Sala Seminari (Dip. Matematica)
<http://www.dm.unipi.it/webnew/it/aula/sala-seminari-dip-matematica>
Slice-torus link invariants and Whitehead doubles
<http://www.dm.unipi.it/webnew/it/seminari/slice-torus-link-invariants-and-w…>
Cari tutti,
vi segnalo questa attività per il ciclo di seminari dei Baby Geometri:
Lunedì 7 Maggio alle 16:30
presso l'Aula Seminari del Dipartimento di Matematica
Gianluca Faraco (Università degli Studi di Parma)
terrà un seminario dal titolo:
Be hyperbolic! Be pure!
di cui riporto l'abstract:
In this talk we will talk about the relationship between hyperbolic
cone-structures and their holonomy representations. Any hyperbolic
structure on a given closed compact and orientable surface S induces in a
very natural way a representation of the fundamental group in the Lie
group PSL(2,R), which encodes geometric data about the structure. The
reverse problem to recover a hyperbolic cone-structure from a given
representation is more arduous and longer. Even worse it is not always
possible. In the first part of this talk we will consider this problem
from a general viewpoint giving examples of representations that not arise
as the holonomy of hyperbolic cone-structure. In the second part we focus
our attention to a very special class of representations, namely purely
hyperbolic representations.
Tutti gli interessati sono invitati a partecipare.
Per saperne di più sui prossimi seminari scrivete a
babygeometri(a)cs.dm.unipi.it
<https://student-web1.dm.unipi.it/squirrelmail/src/compose.php?send_to=babyg…>
o consultate la nostra pagina web:
http://people.dm.unipi.it/babygeometri/
Saluti,
Giulio Belletti, Edoardo Fossati e Marco Moraschini