BEGIN:VCALENDAR
VERSION:2.0
PRODID:researchseminars.org
CALSCALE:GREGORIAN
X-WR-CALNAME:researchseminars.org
BEGIN:VEVENT
SUMMARY:Federico Caucci (Florence)
DTSTART:20200617T130000Z
DTEND:20200617T140000Z
DTSTAMP:20260404T095336Z
UID:GeoSem/1
DESCRIPTION:Title: Derived invariance and the Albanese morphism\nby Federico Caucci
(Florence) as part of Geometry Seminar - University of Florence\n\n\nAbst
ract\nI will give an overview on the derived invariance problem: how much
of the geometry of a smooth complex projective variety is determined by it
s bounded derived category? I will recall the main theorems and conjecture
s of this area. Finally\, I will present the results of a joint work in pr
ogress with L. Lombardi and G. Pareschi\, involving the Albanese morphism.
\n
LOCATION:https://stable.researchseminars.org/talk/GeoSem/1/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Marco Radeschi (University of Notre Dame)
DTSTART:20200701T123000Z
DTEND:20200701T133000Z
DTSTAMP:20260404T095336Z
UID:GeoSem/2
DESCRIPTION:Title: Invariant Theory without groups\nby Marco Radeschi (University o
f Notre Dame) as part of Geometry Seminar - University of Florence\n\n\nAb
stract\nGiven an orthogonal representation of a Lie group G on a Euclidean
vector space V\, Invariant Theory studies the algebra of G-invariant poly
nomials on V. This setting can be generalized by replacing the orbits of t
he representation with a foliation by the fibers of a manifold submetry\nf
rom the unit sphere S(V)\, and consider the algebra of polynomials that ar
e constant along these fibers (effectively producing an Invariant Theory\,
but without groups)\nIn this talk we will exhibit a surprisingly strong r
elation between the geometric information coming from the submetry and the
algebraic information coming from the corresponding algebra\, with severa
l applications to classical Invariant Theory.\nThis talk is based on a joi
nt work with Ricardo Mendes.\n
LOCATION:https://stable.researchseminars.org/talk/GeoSem/2/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Francesco Pediconi (Università di Firenze)
DTSTART:20201015T123000Z
DTEND:20201015T133000Z
DTSTAMP:20260404T095336Z
UID:GeoSem/3
DESCRIPTION:Title: On cohomogeneity one Hermitian metrics\nby Francesco Pediconi (U
niversità di Firenze) as part of Geometry Seminar - University of Florenc
e\n\nAbstract: TBA\n
LOCATION:https://stable.researchseminars.org/talk/GeoSem/3/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Romina Arroyo (Universidad Nacional de C\\'ordoba and CONICET)
DTSTART:20201029T140000Z
DTEND:20201029T150000Z
DTSTAMP:20260404T095336Z
UID:GeoSem/4
DESCRIPTION:Title: The prescribed Ricci curvature problem for naturally reductive metri
cs on simple Lie groups\nby Romina Arroyo (Universidad Nacional de C\\
'ordoba and CONICET) as part of Geometry Seminar - University of Florence\
n\n\nAbstract\nThe prescribed Ricci curvature problem consists in finding
a Riemannian metric $g$ and a real number $c>0$ satisfying\n\\[\n\\operato
rname{Ric} (g) = c T\,\n\\]\nfor some fixed symmetric $(0\, 2)$-tensor fie
ld $T$ on a manifold $M\,$ where $\\operatorname{Ric} (g)$ denotes the Ric
ci curvature of $g.$\n\nThe aim of this talk is to discuss this problem wi
thin the class of left-invariant naturally reductive metrics when $M$ is a
simple Lie group\, and present recently obtained results in this setting.
\n\nThis talk is based on joint works with Mark Gould (The University of
Queensland) Artem Pulemotov (The University of Queensland) and Wolfgang Zi
ller (University of Pennsylvania).\n
LOCATION:https://stable.researchseminars.org/talk/GeoSem/4/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Sammy Sbiti (University of Pennsylvania)
DTSTART:20201105T150000Z
DTEND:20201105T160000Z
DTSTAMP:20260404T095336Z
UID:GeoSem/5
DESCRIPTION:Title: On the Ricci flow of homogeneous metrics on spheres\nby Sammy Sb
iti (University of Pennsylvania) as part of Geometry Seminar - University
of Florence\n\nAbstract: TBA\n
LOCATION:https://stable.researchseminars.org/talk/GeoSem/5/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Daniele Angella (Università di Firenze)
DTSTART:20201112T150000Z
DTEND:20201112T160000Z
DTSTAMP:20260404T095336Z
UID:GeoSem/6
DESCRIPTION:Title: On the Chern-Ricci flow on Inoue surfaces\nby Daniele Angella (U
niversità di Firenze) as part of Geometry Seminar - University of Florenc
e\n\nAbstract: TBA\n
LOCATION:https://stable.researchseminars.org/talk/GeoSem/6/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Mario Garcia-Fernandez (Universidad Autónoma de Madrid)
DTSTART:20201117T140000Z
DTEND:20201117T150000Z
DTSTAMP:20260404T095336Z
UID:GeoSem/7
DESCRIPTION:Title: Kähler moduli spaces on non-Kähler Calabi-Yau manifolds\nby Ma
rio Garcia-Fernandez (Universidad Autónoma de Madrid) as part of Geometry
Seminar - University of Florence\n\n\nAbstract\nModuli spaces of Calabi-Y
au metrics play a prominent role in geometry and mathematical physics. The
interest on these moduli spaces lies in their rich geometric structure\,
related to mirror symmetry and enumerative geometry. In this talk I will e
xplain how the Kähler metric on the “Kähler moduli space” of a Calab
i-Yau manifold can be obtained from symplectic reduction. I will then move
on to show how a suitable choice of vector bundle allows us to extend thi
s construction to non-Kähler Calabi-Yau manifolds\, by means of the Hull-
Strominger moduli space. Based on joint work with Rubio (UAB) and Tipler (
UBO) in arXiv:2004.11399\, and ongoing work with Raúl González Molina.\n
LOCATION:https://stable.researchseminars.org/talk/GeoSem/7/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Mehdi Lejmi (Bronx Community College of City University of New Yor
k)
DTSTART:20201126T150000Z
DTEND:20201126T160000Z
DTSTAMP:20260404T095336Z
UID:GeoSem/8
DESCRIPTION:Title: Conformally Kähler Einstein-Maxwell metrics on blow-ups\nby Meh
di Lejmi (Bronx Community College of City University of New York) as part
of Geometry Seminar - University of Florence\n\n\nAbstract\nConformally K
ähler Hermitian metrics of constant Riemannian scalar curvature and J-inv
ariant Ricci are called conformally Kähler Einstein Maxwell metrics. In t
his talk\, we discuss deformations and possible construction of such metri
cs on blow-ups. This is a joint work in progress with Abdellah Lahdili.\n
LOCATION:https://stable.researchseminars.org/talk/GeoSem/8/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Francesco Bei (Università di Roma La Sapienza)
DTSTART:20201210T133000Z
DTEND:20201210T143000Z
DTSTAMP:20260404T095336Z
UID:GeoSem/9
DESCRIPTION:Title: On the spectral theory and analytic K-homology of complex spaces
\nby Francesco Bei (Università di Roma La Sapienza) as part of Geometry S
eminar - University of Florence\n\n\nAbstract\nLet $(X\, h)$ be a compact
and irreducible Hermitian complex space. In the last\nthirty years\, motiv
ated among other things by the Cheeger-Goresky-MacPherson\nconjecture and
the Riemann-Roch theorem of Baum-Fulton-MacPherson\, the $L^2$-\ntheory of
the Hodge-de Rham operator $d + d^t$\, the Hodge-Dolbeault operator $\\ov
erline\\partial + \\overline\\partial^t$ and the associated Laplacians on
$(X\, h)$ has been the subject of many investigations. In the first part o
f this talk we will report about some recent results concerning the existe
nce of self-adjoint extensions of the Hodge-\nKodaira Laplacian with entir
ely discrete spectrum. Then in the second part we will describe some appli
cations to the K-homology of X. In particular assuming $\\dim(sing(X)) = 0
$ we will show how the operator $\\overline\\partial+\\overline\\partial^t
$ induces an analytic K-homology class in $K^{an}_{0}(X)$ and we will give
a geometric interpretation of this class in terms of a resolution of $X$.
\n
LOCATION:https://stable.researchseminars.org/talk/GeoSem/9/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Giorgio Ottaviani (Università di Firenze)
DTSTART:20201112T140000Z
DTEND:20201112T150000Z
DTSTAMP:20260404T095336Z
UID:GeoSem/10
DESCRIPTION:Title: Singular t-ples of tensors and their geometry\nby Giorgio Ottav
iani (Università di Firenze) as part of Geometry Seminar - University of
Florence\n\n\nAbstract\nThere is a natural invariant metric on the space o
f tensors\, called Frobenius metric. In optimization setting one considers
the (complex) critical points on the Segre variety of the distance functi
on from a given tensor\, they are called singular t-ples\, among them ther
e is the best rank one approximation. Their number is the EDdegree of the
Segre variety. The geometry of the critical points is appealing\, since th
ey lie in a linear space called critical space\, which has dimension small
er than the number of critical points\, in other words the critical points
are linearly dependent\, unless the matrix case. We expose some propertie
s of singular t-ples. In a following talk Emanuele Ventura will lecture ab
out the asymptotic behaviour of EDdegree and other more advanced propertie
s.\n\nApplied Algebraic Geometry 2020-2021:\nhttp://web.math.unifi.it/grup
pi/algebraic-geometry/AppliedAlgebraicGeometry20202021.html\n
LOCATION:https://stable.researchseminars.org/talk/GeoSem/10/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Giovanni Bazzoni (Università dell'Insubria)
DTSTART:20201203T133000Z
DTEND:20201203T143000Z
DTSTAMP:20260404T095336Z
UID:GeoSem/11
DESCRIPTION:Title: Homotopy Invariants and almost non-negative curvature\nby Giova
nni Bazzoni (Università dell'Insubria) as part of Geometry Seminar - Univ
ersity of Florence\n\n\nAbstract\nAlmost non-negative sectional curvature
(ANSC) is a curvature condition on a Riemannian manifold\, which encompass
es both the almost flat and the non-negatively curved case. It was shown i
n a remarkable paper by Kapovitch\, Petrunin and Tuschmann that\, modulo s
ome technical details\, a compact ANSC manifold is a fiber bundle over a n
ilmanifold\, and that the fiber satisfies a curvature condition only sligh
tly more general than ANSC. In this talk\, based on joint work with G. Lup
ton and J. Oprea\, we will discuss such manifolds from the point of view o
f Rational Homotopy Theory\, presenting various invariants of bundles of s
uch type\, and proving a (rational) Bochner-type theorem.\n
LOCATION:https://stable.researchseminars.org/talk/GeoSem/11/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Francesco Pediconi (Università di Firenze)
DTSTART:20210114T133000Z
DTEND:20210114T143000Z
DTSTAMP:20260404T095336Z
UID:GeoSem/12
DESCRIPTION:Title: Hermitian curvature flow on locally homogeneous complex surfaces\nby Francesco Pediconi (Università di Firenze) as part of Geometry Semi
nar - University of Florence\n\n\nAbstract\nThe Hermitian curvature flow (
"HCF" shortly) is a strictly\nparabolic flow of Hermitian metrics\, introd
uced by Streets and Tian\,\nwhich evolves an initial Hermitian metric in t
he direction of its\nsecond Chern-Ricci curvature tensor with some first-o
rder terms in the\ntorsion. In this talk\, we study the long-time behavior
of locally\nhomogeneous non-Kähler solutions to the HCF on compact comp
lex\nsurfaces and\, after a suitable normalization\, we compute the\nGromo
v-Hausdorff limit of those which are immortal. This is a joint\nwork with
Mattia Pujia.\n\nSeminario PRIN2017 "Real and Complex Manifolds: Topology\
, Geometry and Holomorphic Dynamics"\n
LOCATION:https://stable.researchseminars.org/talk/GeoSem/12/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Antonella Nannicini (Università di Firenze)
DTSTART:20210128T133000Z
DTEND:20210128T143000Z
DTSTAMP:20260404T095336Z
UID:GeoSem/13
DESCRIPTION:Title: Almost complex setting for Kodaira dimension\nby Antonella Nann
icini (Università di Firenze) as part of Geometry Seminar - University of
Florence\n\n\nAbstract\nThe concept of Kodaira dimension has been recentl
y extended from complex to almost complex\ncontext by H. Chen and W. Zhang
. In this talk\, first we describe similarities and differences between Ko
daira dimension for complex and almost complex manifolds\, then we focus o
n compact 4-dimensional solvmanifolds without any integrable almost comple
x structure. We present recent results for Kodaira dimension of certain fa
milies of almost complex structures\, providing a twistorial description.
Also we describe some aspects of the correspondence between Kodaira dimens
ion and curvature. Results are based on joint works with A. Tomassini and
A. Cattaneo.\n
LOCATION:https://stable.researchseminars.org/talk/GeoSem/13/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Lucas Kaufmann Sacchetto (National University of Singapore)
DTSTART:20210204T133000Z
DTEND:20210204T143000Z
DTSTAMP:20260404T095336Z
UID:GeoSem/14
DESCRIPTION:Title: Currents\, their intersection and applications\nby Lucas Kaufma
nn Sacchetto (National University of Singapore) as part of Geometry Semina
r - University of Florence\n\n\nAbstract\nPositive closed currents are cen
tral objects in pluripotential theory and modern complex analysis. They ge
neralize both smooth differential forms and subvarieties. Given two curren
ts it is of central importance to understand when a meaningful notion of
intersection (or wedge product) between them can be given. This is useful
for instance in producing invariant measures for dynamical systems and in
the study of the complex Monge-Ampère equation with singular data.\n\nIn
this talk I aim to overview some basic facts about currents in complex ana
lysis (including their definition) and recent approaches to their intersec
tion theory. I'll also mention some applications to geometry and to the d
ynamics of maps and foliations.\n
LOCATION:https://stable.researchseminars.org/talk/GeoSem/14/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Fabio Tonini (Università di Firenze)
DTSTART:20210304T133000Z
DTEND:20210304T143000Z
DTSTAMP:20260404T095336Z
UID:GeoSem/15
DESCRIPTION:Title: Fundamental groups in algebraic geometry\nby Fabio Tonini (Univ
ersità di Firenze) as part of Geometry Seminar - University of Florence\n
\n\nAbstract\nI plan to introduce and discuss several notions of fundament
al group in the context of algebraic geometry\, for example the Grothendie
ck-étale fundamental group and the Nori fundamental group scheme\, follow
ing the parallel with the classical topological fundamental group and the
theory of topological (Galois) coverings.\n
LOCATION:https://stable.researchseminars.org/talk/GeoSem/15/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Scott Wilson (Queens College and CUNY)
DTSTART:20210414T133000Z
DTEND:20210414T143000Z
DTSTAMP:20260404T095336Z
UID:GeoSem/16
DESCRIPTION:Title: Small Nijenhuis tensors on compact almost complex manifolds with no
complex structure\nby Scott Wilson (Queens College and CUNY) as part
of Geometry Seminar - University of Florence\n\n\nAbstract\nI will present
several examples of compact almost complex manifolds with a $1$-parameter
family of almost complex structures having arbitrarily small Nijenhuis te
nsors in the $C^0$-norm. The $4$-dimensional examples possess no complex s
tructure\, while the $6$-dimensional examples do not possess left invarian
t complex structures\, and whether they possess complex structures appears
to be unknown. This is joint work with Luis Fernandez and Tobias Shin.\n
LOCATION:https://stable.researchseminars.org/talk/GeoSem/16/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Ramiro Lafuente (The University of Queensland)
DTSTART:20210211T080000Z
DTEND:20210211T090000Z
DTSTAMP:20260404T095336Z
UID:GeoSem/17
DESCRIPTION:Title: On the signature of the Ricci curvature on nilmanifolds\nby Ram
iro Lafuente (The University of Queensland) as part of Geometry Seminar -
University of Florence\n\n\nAbstract\nIn this talk we will explain the sol
ution to the following problem: Given an arbitrary nilpotent Lie group\,
determine all possible signatures of the Ricci curvature of left invariant
metrics on it. The solution involves constructing invariant metrics with
many zeros in their Ricci curvature\, for which we use ideas from GIT\, an
d then an Implicit function theorem argument.\n
LOCATION:https://stable.researchseminars.org/talk/GeoSem/17/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Uwe Semmelmann (Universität Stuttgart)
DTSTART:20210225T133000Z
DTEND:20210225T143000Z
DTSTAMP:20260404T095336Z
UID:GeoSem/18
DESCRIPTION:Title: Stability of Einstein metrics\nby Uwe Semmelmann (Universität
Stuttgart) as part of Geometry Seminar - University of Florence\n\n\nAbstr
act\nEinstein metrics can be characterised as critical points of\nthe (nor
malised) total scalar curvature functional. They are always\nsaddle points
. However\, there are Einstein metrics which are local\nmaxima of the func
tional restricted to metrics of fixed\nvolume and constant scalar curvatur
e. These are by definition stable\nEinstein metrics. Stability can equival
ently be characterised by\na spectral condition for the Lichnerowicz Lapla
cian on divergence- and\ntrace-free symmetric 2-tensors\, i.e. on so-calle
d tt-tensors:\nan Einstein metric is stable if twice the Einstein constant
is a lower\nbound for this operator. Stability is also related to Perelma
n's\n\\nu entropy and dynamical stability with respect to the Ricci flow.\
n\nIn my talk I will discuss the stability condition. I will present a\nre
cent result obtained with G. Weingart\, which completes the work\nof Koiso
on the classification of stable compact symmetric spaces.\nMoreover\, I w
ill describe an interesting relation between instability\nand the existenc
e of harmonic forms. This is done in the case of nearly\nKähler\, Einste
in-Sasaki and nearly G_2 manifolds. If\ntime permits I will also explain t
he instability of the Berger space\nSO(5)/SO(3)\, which is a homology sphe
re. In this case\ninstability surprisingly is related to the existence of
Killing tensors.\nThe latter results are contained in joint work with\nM.
Wang and C. Wang.\n
LOCATION:https://stable.researchseminars.org/talk/GeoSem/18/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Chengjian Yao (ShanghaiTech University)
DTSTART:20210311T130000Z
DTEND:20210311T140000Z
DTSTAMP:20260404T095336Z
UID:GeoSem/19
DESCRIPTION:Title: Einstein-Bogomol’nyi equation and Gravitating Vortex equations on
Riemann surfaces\nby Chengjian Yao (ShanghaiTech University) as part
of Geometry Seminar - University of Florence\n\n\nAbstract\nThe Einstein
’s Fields Equation coupled with an Abelian gauge field and a Higgs field
possesses a special type of solution\, mathematically known as Einstein-B
ogomol’nyi equation and physically known as Cosmic Strings. In this talk
\, I will present some existence theorems for such equation and also its c
lose companion Gravitating Cortex equations\, introduced from a moment map
picture. This is based on the joint work with Garcia-Fernandez and Pingal
i.\n
LOCATION:https://stable.researchseminars.org/talk/GeoSem/19/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Jorge Lauret (Universidad Nacional de Córdoba)
DTSTART:20210408T123000Z
DTEND:20210408T133000Z
DTSTAMP:20260404T095336Z
UID:GeoSem/20
DESCRIPTION:Title: On the stability of compact homogeneous Einstein manifolds\nby
Jorge Lauret (Universidad Nacional de Córdoba) as part of Geometry Semina
r - University of Florence\n\n\nAbstract\nAfter some quick preliminaries o
n the general stability theory of compact Einstein manifolds\, we will foc
us on the homogeneous case and give a formula for the Lichnerowicz Laplaci
an of a G-invariant metric on a compact homogeneous space M=G/K\, restrict
ed to the subspace of G-invariant TT-tensors\, which was obtained via the
moving bracket approach. \n\nAs an application\, we study the stability t
ype of G-invariant Einstein metrics on M\, which are known to be the criti
cal points of the scalar curvature restricted to unit volume G-invariant m
etrics. The naturally reductive case presents some advantages. \n\nThis
is joint work with Cynthia Will and Emilio Lauret.\n
LOCATION:https://stable.researchseminars.org/talk/GeoSem/20/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Caterina Stoppato (Università di Firenze)
DTSTART:20210325T133000Z
DTEND:20210325T143000Z
DTSTAMP:20260404T095336Z
UID:GeoSem/21
DESCRIPTION:Title: Dual quaternions and slice functions: theory and applications\n
by Caterina Stoppato (Università di Firenze) as part of Geometry Seminar
- University of Florence\n\n\nAbstract\nThe talk will present some recent
results in the theory of slice functions\nover alternative *-algebras\, in
troduced by Ghiloni and Perotti in 2011 as\na generalization of the theory
of quaternionic slice regular functions\nlaunched by Gentili and Struppa
in 2006.\nThe talk will focus on the algebra of dual quaternions. For this
algebra\,\nan explicit classification of zero divisors is available. This
makes it\npossible to study the zero sets of slice functions\, slice regu
lar functions\nand polynomials over this algebra in full detail.\nThis stu
dy can be applied to the open problem of factorizing motion\npolynomials o
ver dual quaternions. The polynomials in this class\,\nintroduced by Heged
üs\, Schicho\, and Schröcker in 2013\, correspond to\nrational rigid bod
y motions in the Euclidean 3-space. Their factorizations\ncorrespond to li
nkages producing the same motions\, so their\nclassification is relevant t
o mechanism science.\nThe main results presented have been proven jointly
with Graziano\nGentili and Tomaso Trinci.\n
LOCATION:https://stable.researchseminars.org/talk/GeoSem/21/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Xuemiao Chen
DTSTART:20210422T123000Z
DTEND:20210422T133000Z
DTSTAMP:20260404T095336Z
UID:GeoSem/22
DESCRIPTION:Title: Singularities of Hermitian-Yang-Mills connections\nby Xuemiao C
hen as part of Geometry Seminar - University of Florence\n\n\nAbstract\nAf
ter introducing some background about stable bundles and HYM connections\,
I will explain both the analytic and algebraic sides when studying singul
arities of HYM connections. \n\nIt turns out that local algebraic invarian
ts can be extracted to characterize the analytic side. In particular\, the
analytic tangent cone is an algebraic invariant. (Based on joint works wi
th Song Sun.)\n
LOCATION:https://stable.researchseminars.org/talk/GeoSem/22/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Filippo Fagioli (Università di Roma La Sapienza)
DTSTART:20210506T123000Z
DTEND:20210506T133000Z
DTSTAMP:20260404T095336Z
UID:GeoSem/23
DESCRIPTION:Title: Pointwise push-forward formulae for flag bundles and their applicat
ions in positivity\nby Filippo Fagioli (Università di Roma La Sapienz
a) as part of Geometry Seminar - University of Florence\n\n\nAbstract\nIn
this talk\, after recalling some basics on flag bundles associated to holo
morphic vector bundles\, I present a result that provides the pointwise\,
Hermitian version of a universal push-forward formula for flag bundles val
id in cohomology. As an application\, I explain how to use the above resul
t to obtain the positivity of several polynomials in the Chern forms of a
Griffiths positive vector bundle. This gives a partial confirmation of a c
onjecture proposed by Griffiths in the late sixties\, which has raised int
erest in the past as well as in recent years. This talk is based on a join
t work with S. Diverio.\n
LOCATION:https://stable.researchseminars.org/talk/GeoSem/23/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Francesca Salvatore (Università di Torino)
DTSTART:20210513T123000Z
DTEND:20210513T133000Z
DTSTAMP:20260404T095336Z
UID:GeoSem/24
DESCRIPTION:Title: Closed G2-structures on unimodular with non-trivial center Lie grou
ps\nby Francesca Salvatore (Università di Torino) as part of Geometry
Seminar - University of Florence\n\n\nAbstract\nClosed $G_2$-structures a
rise as a natural generalization of torsion-free $G_2$-structures on seven
-dimensional smooth manifolds. In this talk\, I shall focus on Lie groups
with non-trivial\n\ncenter endowed with a left-invariant closed $G_2$-stru
cture. After highlighting the relation\nwith six-dimensional geometry\, I
shall present a classification result in the unimodular case\nas well as n
ew compact examples. Results about Laplacian solitons\, which correspond t
o\nself-similar solutions of the $G_2$-Laplacian flow introduced by Bryant
\, are also included. This is joint work with A. Fino and A. Raffero.\n
LOCATION:https://stable.researchseminars.org/talk/GeoSem/24/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Jonas Stelzig
DTSTART:20211012T123000Z
DTEND:20211012T133000Z
DTSTAMP:20260404T095336Z
UID:GeoSem/25
DESCRIPTION:Title: Linear combinations of cohomological invariants of compact complex
manifolds\nby Jonas Stelzig as part of Geometry Seminar - University o
f Florence\n\n\nAbstract\nWe will give answers to the following three ques
tions about\nthe set of all compact complex manifolds of a given dimension
:\n\n\n(i) Which linear relations between Hodge\, Betti and Chern numbers
are\nuniversally satisfied?\n\n(ii) Which linear combinations of Hodge\, B
etti and Chern numbers are\nbimeromorphism invariants?\n\n(iii) Which line
ar combinations of Hodge\, Betti and Chern numbers are\ntopological invari
ants?\n\n\nWe also present a strategy to answer the analogous questions wh
en asked\nabout `all' cohomological invariants (including e.g. the dimensi
ons of\nhigher pages of the Frölicher spectral sequence or Bott Chern and
Aeppli\ncohomology). We carry this out to obtain answers in low dimension
s\, with\nanswers in any dimension being reduced to specific construction
problems.\n
LOCATION:https://stable.researchseminars.org/talk/GeoSem/25/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Alexandra Otiman
DTSTART:20211019T123000Z
DTEND:20211019T133000Z
DTSTAMP:20260404T095336Z
UID:GeoSem/26
DESCRIPTION:Title: New constructions in non-Kähler toric geometry\nby Alexandra O
timan as part of Geometry Seminar - University of Florence\n\n\nAbstract\n
Kato manifolds are compact complex manifolds containing a \nglobal spheric
al shell. Their modern study has been widely carried out \nin complex dime
nsion 2 and originates in the seminal work of Inoue\, \nKato\, Nakamura an
d Hirzebruch.\nIn this talk I plan to describe a special class of Kato man
ifolds in \narbitrary complex dimension\, whose construction arises from t
oric \ngeometry. Using the toric language\, I will present several of thei
r \nanalytic and geometric properties\, including existence of special \nc
omplex submanifolds and partial results on their Dolbeault \ncohomology. M
oreover\, since they are compact complex manifolds of \nnon-Kahler type\,
I will investigate what special Hermitian metrics \nthey support.\n
LOCATION:https://stable.researchseminars.org/talk/GeoSem/26/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Gao Chen
DTSTART:20211026T123000Z
DTEND:20211026T133000Z
DTSTAMP:20260404T095336Z
UID:GeoSem/27
DESCRIPTION:Title: The J-equation and deformed Hermitian-Yang-Mills equation\nby G
ao Chen as part of Geometry Seminar - University of Florence\n\n\nAbstract
\nThe deformed Hermitian-Yang-Mills (dHYM) equation is the mirror equation
for the special Lagrangian equation. The ”small radius limit” of the
dHYM equation is the J-equation\, which is closely related to the constant
scalar curvature Kaehler (cscK) metrics. In this talk\, I will explain my
recent result that the solvability of the J-equation is equivalent to a n
otion of stability. I will also explain my similar result on the supercrit
ical dHYM equation as well as the application of my results to the cscK pr
oblem.\n
LOCATION:https://stable.researchseminars.org/talk/GeoSem/27/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Miron Stanciu
DTSTART:20211109T133000Z
DTEND:20211109T143000Z
DTSTAMP:20260404T095336Z
UID:GeoSem/28
DESCRIPTION:Title: Vaisman's theorem for lcK spaces with singularities\nby Miron S
tanciu as part of Geometry Seminar - University of Florence\n\n\nAbstract\
nVaisman’s theorem for locally conformally K\\" ahler (lcK) compact mani
folds states that any lcK metric on a compact complex manifold which admit
s a K\\" ahler metric is\, in fact\, globally conformally K\\" ahler. In t
his talk\, I will show the steps we used to extend this result to compact
complex spaces with singularities. This is a joint work with Ovidiu Preda.
\n
LOCATION:https://stable.researchseminars.org/talk/GeoSem/28/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Ruobing Zhang
DTSTART:20211116T133000Z
DTEND:20211116T143000Z
DTSTAMP:20260404T095336Z
UID:GeoSem/29
DESCRIPTION:Title: Collapsing geometry of hyperkaehler four-manifolds\nby Ruobing
Zhang as part of Geometry Seminar - University of Florence\n\n\nAbstract\n
This talk focuses on the recent resolution of the following three well-kno
wn conjectures in the study of Ricci-flat four manifolds (joint with Song
Sun). \n\n(1) Any volume collapsed limit of unit-diameter hyperkaehler met
rics on the K3 manifold is isometric to one of the following: the quotient
of a flat 3-torus by an involution\, a singular special Kaehler metric on
the 2-sphere\, or the unit interval. \n(2) Any complete non-compact hyper
kaehler 4-manifold with quadratically integrable curvature must have one o
f the following asymptotic model geometries: ALE\, ALF\, ALG\, ALH\, ALG*
and ALH*.\n(3) Any gravitational instanton is holomorphic to an open dense
subset of some compact algebraic surface.\n\nWith the above classificatio
n results\, we obtain a rather complete picture of the collapsing geometry
of hyperkaehler four manifolds.\n
LOCATION:https://stable.researchseminars.org/talk/GeoSem/29/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Anusha Krishnan
DTSTART:20211207T133000Z
DTEND:20211207T143000Z
DTSTAMP:20260404T095336Z
UID:GeoSem/30
DESCRIPTION:Title: Positive sectional curvature and Ricci flow\nby Anusha Krishnan
as part of Geometry Seminar - University of Florence\n\n\nAbstract\nThe p
reservation of positive curvature conditions under the Ricci flow has been
an important ingredient in applications of the flow to solving problems i
n geometry and topology. Works by Hamilton and others established that cer
tain positive curvature conditions are preserved under the flow\, culminat
ing in Wilking's unified\, Lie algebraic approach to proving invariance of
positive curvature conditions. Yet\, some questions remain. In this talk\
, we describe sec > 0 initial metrics on S^4\, where the condition of sec
> 0 is not preserved under the Ricci flow. Previously\, examples of such b
ehaviour were known for sec \\geq 0\, and for sec > 0 in dimension 6 and a
bove. This is joint work with Renato Bettiol.\n
LOCATION:https://stable.researchseminars.org/talk/GeoSem/30/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Lucía Martín Merchán
DTSTART:20211123T133000Z
DTEND:20211123T143000Z
DTSTAMP:20260404T095336Z
UID:GeoSem/31
DESCRIPTION:Title: A compact non-formal closed G_2 manifold with b_1=1\nby Lucía
Martín Merchán as part of Geometry Seminar - University of Florence\n\n
\nAbstract\nA G_2 structure on a 7-dimensional Riemannian manifold determi
ned by a certain type of 3-form φ. These are classified into 16 types acc
ording to PDEs involving φ\; for instance\, the G_2 structure is torsion-
free if φ is parallel\, closed if φ is closed and cocalibrated if φ i
s co-closed.\nThis talk contributes to understanding topological propertie
s of compact manifolds with a closed G_2 structure that cannot be endowed
with any torsion-free G_2 structure. Namely\, we construct such a manifold
that is non-formal and has first Betti number b_1=1. The starting point i
s a nilmanifold (M\,φ) with a closed G_2 structure that admits an involut
ion preserving φ such that the quotient M/Z_2 is a non-formal orbifold w
ith b_1=1. Then we perform a resolution of these singularities obtaining a
manifold endowed with a closed G_2 structure\; we finally prove that the
resolution verifies the same topological properties and do not admit any t
orsion-free G_2 structure.\n
LOCATION:https://stable.researchseminars.org/talk/GeoSem/31/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Ioannis Chrysikos
DTSTART:20211130T133000Z
DTEND:20211130T143000Z
DTSTAMP:20260404T095336Z
UID:GeoSem/32
DESCRIPTION:Title: Almost hypercomplex/quaternionic skew-Hermitian structures\nby
Ioannis Chrysikos as part of Geometry Seminar - University of Florence\n\n
\nAbstract\nThis talk provides a short introduction to the differential g
eometry of 4n-dimensional manifolds admitting \na SO*(2n)-structure\, or
a SO*(2n)Sp(1)-structure\, where SO*(2n) denotes the quaternionic real for
m of SO(2n\, C). \nSuch G-structures form the symplectic analog of the we
ll-known almost hypercomplex/quaternionic Hermitian structures\, and we c
all them almost hypercomplex/quaternionic skew-Hermitian structures\, res
pectively. \nWe describe the basic data encoding such geometric structur
es\, and then we focus on their intrinsic torsion and related 1st-order in
tegrability conditions. Some examples and classification examples will be
also discusssed.\nThis talk is based on a joint work with J. Gregorovič (
UHK) and H. Winther (Masaryk).\n
LOCATION:https://stable.researchseminars.org/talk/GeoSem/32/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Valerio Melani
DTSTART:20211214T133000Z
DTEND:20211214T143000Z
DTSTAMP:20260404T095336Z
UID:GeoSem/33
DESCRIPTION:Title: Weinstein's "Poisson category" in derived geometry\nby Valerio
Melani as part of Geometry Seminar - University of Florence\n\n\nAbstract\
nMotivated by deformation quantization\, Weinstein initiated the study of\
nthe "Poisson category". This should be a category whose objects are\nPois
son manifolds\, and whose morphisms are coisotropic correspondences.\nUnfo
rtunately\, in the general case there is no such category. In fact\,\ncomp
osition of morphisms by fiber products is not always available\, and\none
needs to put strong enough "clean intersection" hypothesis to make\nit pos
sible. In this talk\, we present a realization of the Poisson\ncategory in
the context of derived (algebraic) geometry\, which is a\nhomotopical gen
eralization of "classical" algebraic geometry. The talk\nwill be based on
joint work(s) with Rune Haugseng and Pavel Safronov.\n
LOCATION:https://stable.researchseminars.org/talk/GeoSem/33/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Xi Sisi Shen
DTSTART:20220224T150000Z
DTEND:20220224T160000Z
DTSTAMP:20260404T095336Z
UID:GeoSem/34
DESCRIPTION:Title: Metrics of constant Chern scalar curvature and a Chern-Calabi flow<
/a>\nby Xi Sisi Shen as part of Geometry Seminar - University of Florence\
n\n\nAbstract\nWe discuss the existence problem of constant Chern scalar c
urvature metrics on a compact complex manifold. We prove a priori estimate
s for these metrics conditional on an upper bound on the entropy\, extendi
ng a recent result by Chen-Cheng in the Kähler setting. In addition\, we
show how these estimates can be used to prove a convergence result for a H
ermitian analogue of the Calabi flow on compact complex manifolds with van
ishing first Bott-Chern class.\n
LOCATION:https://stable.researchseminars.org/talk/GeoSem/34/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Bertrand Toën
DTSTART:20220303T133000Z
DTEND:20220303T143000Z
DTSTAMP:20260404T095336Z
UID:GeoSem/35
DESCRIPTION:Title: Integrability of singular foliations\nby Bertrand Toën as part
of Geometry Seminar - University of Florence\n\n\nAbstract\nIn this talk\
, I will introduce derived foliations (in the\nalgebraic and complex analy
tic settings)\,\na general notion of foliations for which leaves are allow
ed to be\nsingular subvarieties. I will explain how\nthese can be globally
integrated by contructing a monodromy and a\nholonomy groupoid. When the
derived foliation\nis algebraic I'll explain how a Riemann-Hilbert corresp
ondence can be\nused in order to describe\n(part of) the holonomy using pu
rely algebraic constructions. Joint with\nG. Vezzosi.\n
LOCATION:https://stable.researchseminars.org/talk/GeoSem/35/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Xiangwen Zhang
DTSTART:20220310T163000Z
DTEND:20220310T173000Z
DTSTAMP:20260404T095336Z
UID:GeoSem/36
DESCRIPTION:Title: A geometric flow for Type IIA superstrings\nby Xiangwen Zhang a
s part of Geometry Seminar - University of Florence\n\n\nAbstract\nThe equ
ations of flux compactifications of Type IIA superstrings were written dow
n by Tomasiello and Tseng-Yau.\nTo study these equations\, we introduce a
natural geometric flow on symplectic Calabi-Yau 6-manifolds. In this talk\
, we will\ndiscuss the recent progress on the study of this Type IIA flow.
This is based on joint work with Fei\, Phong and Picard.\n
LOCATION:https://stable.researchseminars.org/talk/GeoSem/36/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Arthur Renaudineau
DTSTART:20220324T143000Z
DTEND:20220324T153000Z
DTSTAMP:20260404T095336Z
UID:GeoSem/37
DESCRIPTION:Title: Topology of real algebraic varieties near the tropical limit\nb
y Arthur Renaudineau as part of Geometry Seminar - University of Florence\
n\n\nAbstract\nDescribing all the possible topologies of real projective h
ypersurfaces of fixed degree and dimension is a very difficult problem\, g
oing back to Hilbert's sixteenth problem. We will show some progress on th
is problem when assuming that the variety is closed to some degeneration\,
called tropical limit. We will recall some basics on real algebraic geome
try and tropical geometry and then relate the Betti numbers of a real vari
ety near the tropical limit to the dimension of some tropical homology gro
ups (by the way of a spectral sequence). It is based on joint works with K
ris Shaw and Johannes Rau and Kris Shaw.\n
LOCATION:https://stable.researchseminars.org/talk/GeoSem/37/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Antonio Trusiani
DTSTART:20220328T133000Z
DTEND:20220328T143000Z
DTSTAMP:20260404T095336Z
UID:GeoSem/38
DESCRIPTION:Title: From Kähler-Einstein metrics with prescribed singularities to K-st
ability\nby Antonio Trusiani as part of Geometry Seminar - University
of Florence\n\nAbstract: TBA\n
LOCATION:https://stable.researchseminars.org/talk/GeoSem/38/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Andrea Loi
DTSTART:20220407T123000Z
DTEND:20220407T133000Z
DTSTAMP:20260404T095336Z
UID:GeoSem/39
DESCRIPTION:Title: Kaehler-Ricci soliton indotti da spazi di forme complessi\nby A
ndrea Loi as part of Geometry Seminar - University of Florence\n\n\nAbstra
ct\nDopo aver ricordato i risultati principali sulle metriche di Kahler
e Kaehler-Einstein indotte da spazi di forme complessi finito e infinit
o dimensionali verrà fornita un’idea della dimostrazione di un recente
risultato ottenuto in collaborazione con R. Mossa che mostra che un KRS
indotto da uno spazio di forme complesso finito dimensionale è necessarim
ente banale\, cioè Kahler-Einstein.\n
LOCATION:https://stable.researchseminars.org/talk/GeoSem/39/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Andrei Moroianu
DTSTART:20220428T123000Z
DTEND:20220428T133000Z
DTSTAMP:20260404T095336Z
UID:GeoSem/40
DESCRIPTION:Title: Conformal vector fields on lcK manifolds\nby Andrei Moroianu as
part of Geometry Seminar - University of Florence\n\n\nAbstract\nIt is we
ll known that on compact Kähler manifolds every conformal vector field is
Killing (Lichnerowicz) and every Killing vector field is holomorphic. In
this talk I will extend these results to the locally conformally Kähler s
etting. More precisely\, I will show that any conformal vector field $\\xi
$ on a compact lcK manifold is Killing with respect to the Gauduchon metri
c\, and if the Kähler cover of the manifold is neither flat\, nor hyperk
ähler\, then $\\xi$ is holomorphic. This is joint work with Mihaela Pilca
.\n
LOCATION:https://stable.researchseminars.org/talk/GeoSem/40/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Paul Schwahn
DTSTART:20220505T123000Z
DTEND:20220505T133000Z
DTSTAMP:20260404T095336Z
UID:GeoSem/41
DESCRIPTION:Title: Stability and rigidity of normal homogeneous Einstein manifolds
\nby Paul Schwahn as part of Geometry Seminar - University of Florence\n\n
\nAbstract\nThe stability of an Einstein metric is decided by the (non-)ex
istence of small eigenvalues of the Lichnerowicz Laplacian on tt-tensors.
In the homogeneous setting\, harmonic analysis allows us to approach the c
omputation of these eigenvalues. This easy on symmetric spaces\, but consi
derably more difficult in the non-symmetric case. I review the case of irr
educible symmetric spaces of compact type\, prove the existence of a non-s
ymmetric stable Einstein metric of positive scalar curvature\, and give an
outlook on how to investigate the normal homogeneous case. Furthermore\,
I explore the rigidity and infinitesimal deformability of homogeneous Eins
tein metrics.\n
LOCATION:https://stable.researchseminars.org/talk/GeoSem/41/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Jeff Viaclovsky
DTSTART:20220512T160000Z
DTEND:20220512T170000Z
DTSTAMP:20260404T095336Z
UID:GeoSem/42
DESCRIPTION:Title: Gravitational instantons\, rational surfaces\, and K3 surfaces\
nby Jeff Viaclovsky as part of Geometry Seminar - University of Florence\n
\n\nAbstract\nI will describe some examples of complete non-compact\nRicci
-flat metrics in dimension 4\, which are called "gravitational\ninstantons
." In many cases\, these can be compactified complex\nanalytically to rati
onal surfaces. I will also discuss how these\ngravitational instantons can
arise from sequences of degenerating\nRicci-flat metrics on the compact K
3 surface\, through a process called\n"bubbling".\n
LOCATION:https://stable.researchseminars.org/talk/GeoSem/42/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Bruno Klingler
DTSTART:20220601T123000Z
DTEND:20220601T133000Z
DTSTAMP:20260404T095336Z
UID:GeoSem/43
DESCRIPTION:by Bruno Klingler as part of Geometry Seminar - University of
Florence\n\nAbstract: TBA\n
LOCATION:https://stable.researchseminars.org/talk/GeoSem/43/
END:VEVENT
END:VCALENDAR