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Prossimi seminari del Dipartimento di Matematica
Aprile
dal giorno
28/04/2025
al giorno
30/04/2025
28/04/2025
al giorno
30/04/2025
Conference
da lunedì 28 aprile 2025
a mercoledì 30 aprile 2025
This event is aimed at graduate students and postdoctoral researchers interested in algebra, combinatorics, and their applications. It provides an opportunity to meet peers, share research, and establish new collaborations.
Aprile
29
Martedì
Federico Tufo
nell'ambito della serie: SEMINARIO DI ALGEBRA E GEOMETRIA
Seminario di algebra e geometria
ore
11:00
presso Aula Seminario VIII piano
Aprile
30
Mercoledì
Davide Pastorello
nel ciclo di seminari: SEMINARS IN MATHEMATICAL PHYSICS AND BEYOND
Seminario di fisica matematica
ore
10:00
presso Aula G3 Mineralogia
After an introduction to the notion of quantum generative adversarial networks (qGANs), I will summarize a recent quantum tomography protocol for constructing a classical estimate of a quantum state by performing repeated measurements on a n-qubit system. I will then discuss the convergence of the protocol with respect to a quantum version of the first-order Wasserstein distance, inspired by the theory of optimal mass transport. In particular, I will show how this convergence result allows us to conclude that a qGAN can be equivalently trained using classical estimators of quantum states instead of quantum data. This fact is important in practice, as it enables the training of quantum models without requiring direct access to quantum memory or coherent quantum data streams.
Maggio
05
Lunedì
Tullio Ceccherini-Silberstein
nell'ambito della serie: LOGIC, CATEGORIES, AND APPLICATIONS SEMINAR
ore
14:00
presso Aula Seminario VIII piano
In this completely self-contained talk, I'll discuss various versions of the Garden of Eden theorem,
the Gottschalk surjunctivity conjecture, and Kaplansky's conjecture on stable finiteness of group rings. This will
include a quick review of the notions of amenability and soficity for groups, of the theory of cellular automata, and
entropies of dynamical systems.
Maggio
05
Lunedì
Bufetov
Seminario di analisi matematica
ore
16:00
presso Aula Seminario VIII piano
Maggio
06
Martedì
Francesco Antonio Denisi
nell'ambito della serie: SEMINARIO DI ALGEBRA E GEOMETRIA
Seminario di algebra e geometria
ore
11:00
presso Aula Seminario VIII piano
Mori dream spaces form a class of algebraic varieties that play a significant role in birational geometry, as they exhibit ideal behaviour within the minimal model program. In this talk, we discuss the birational geometry of hypersurfaces in products of weighted projective spaces, focusing particularly on cases where they are Mori dream spaces. We generalize the results obtained by J.C. Ottem and, if time permits, we will address the Kawamata-Morrison cone conjecture for certain anticanonical Calabi-Yau hypersurfaces in products of weighted projective spaces.
Maggio
06
Martedì
Filomena De Filippis
Seminario di analisi matematica
ore
17:00
presso Seminario I
seminario on line •
collegamento al meeting
µ-ellipticity describes certain degenerate forms of ellipticity typical of convex integrals at linear or nearly linear growth, such as the area integral or the iterated logarithmic model. The regularity of solutions to autonomous or totally differentiable problems is classical after Bombieri, De Giorgi and Miranda, Ladyzhenskaya and Ural’tseva and Frehse and Seregin. The anisotropic case is a later achievement of Bildhauer, Fuchs and Mingione, Beck and Schmidt and Gmeineder and Kristensen. However, all the approaches developed so far break down in presence of nondifferentiable ingredients. In particular, Schauder theory for certain significant anisotropic, nonautonomous functionals with Hölder continuous coefficients was only recently obtained by C. De Filippis and Mingione. We will see the validity of Schauder theory for anisotropic problems whose growth is arbitrarily close to linear within the maximal nonuniformity range, and discuss sharp results and insights on more general nonautonomous area type integrals. From a recent, joint work with Cristiana De Filippis (Parma) and Mirco Piccinini (Pisa)
Maggio
07
Mercoledì
Michela Lapenna
nel ciclo di seminari: SEMINARS IN MATHEMATICAL PHYSICS AND BEYOND
Seminario di fisica matematica
ore
11:00
presso Aula Bombelli
Graphs are a powerful data structure for representing relational data and are widely used to describe complex real-world systems. Probabilistic Graphical Models (PGMs) and Graph Neural Networks (GNNs) can both leverage graph-structured data, but their inherent functioning is different.
The question is how do they compare in capturing the information contained in networked datasets?
We address this objective by solving a link prediction task and we conduct three main experiments, on both synthetic and real networks: one focuses on how PGMs and GNNs handle input features, while the other two investigate their robustness to noisy features and increasing heterophily of the graph.
PGMs do not necessarily require features on nodes, while GNNs cannot exploit the network edges alone, and the choice of input features matters. We find that GNNs are outperformed by PGMs when input features are low-dimensional or noisy, mimicking many real scenarios where node attributes might be scalar or noisy.
Then, we find that PGMs are more robust than GNNs when the heterophily of the graph is increased.
Finally, to assess performance beyond prediction tasks, we also compare the two frameworks in terms of their computational complexity and interpretability.
Maggio
08
Giovedì
Ben De Bondt
nell'ambito della serie: LOGIC, CATEGORIES, AND APPLICATIONS SEMINAR
Seminario di logica
ore
14:00
presso Seminario II
Mild (consequences of) forcing axioms imply a general lifting theorem which allows to characterise precisely those homomorphisms between reduced products of countable structures which have a lift that factorises into homomorphisms between the factor structures. We will discuss recent extensions of such lifting theorems to the metric setting and ensuing rigidity phenomena for particular metric reduced product structures of interest.
This is based on joint work with Ilijas Farah and Alessandro Vignati, with Alessandro Vignati, and with Andreas Thom.
Maggio
09
Venerdì
Colin Jahel
nell'ambito della serie: LOGIC, CATEGORIES, AND APPLICATIONS SEMINAR
Seminario di algebra e geometria, logica, sistemi dinamici
ore
14:00
presso VII piano
My talk aim to present our joint work with Matthieu Joseph and Remi Barritault on the actions of non-Archimedean Polish groups. I will first present the notion of dissociation for probability measure-preserving actions, which allows us generalize so-called de Finetti theorems. Then, I will outline the model-theoretical conditions that we know imply dissociation and discuss how they may be improved.
Maggio
12
Lunedì
Pietro Freni
nell'ambito della serie: LOGIC, CATEGORIES, AND APPLICATIONS SEMINAR
Seminario di algebra e geometria, logica
ore
14:00
presso Seminario II
Maggio
13
Martedì
Roberto Svaldi
nell'ambito della serie: SEMINARIO DI ALGEBRA E GEOMETRIA
Seminario di algebra e geometria
ore
11:00
presso Aula Seminario VIII piano
I will explain ideas and techniques behind recent results showing that fibered CY varieties are bounded, starting from the elliptic case and then moving to the case of higher relative dimension.
Maggio
14
Mercoledì
Karl Meerbergen
nel ciclo di seminari: SCUBE
Seminario di analisi numerica
ore
11:30
presso - Aula Da Stabilire -
A nonlinear matrix is a matrix whose entries are nonlinear functions of a parameter. Such problems arise from physics (Schroedinger equation) and mechanical engineering (porous materials, boundary element method, e.g.). The last 20 years, rational approximation methods and linearization were proposed to approximate such matrices by linear pencils of much higher dimensions. Applications are the nonlinear eigenvalue problem, parametric linear systems, frequency sweeping, model order reduction and the solution of time dependent problems with nonlinear frequency dependencies. We give an overview of approximation methods with focus on AAA and Krylov methods that exploit the structure of the linear pencil.
Maggio
16
Venerdì
Patrizio Frosini
nell'ambito della serie: LOGIC, CATEGORIES, AND APPLICATIONS SEMINAR
Seminario di algebra e geometria
ore
14:00
presso Seminario II
Maggio
dal giorno
19/05/2025
al giorno
20/05/2025
19/05/2025
al giorno
20/05/2025
Conference
Knots & Proteins
da lunedì 19 maggio 2025
a martedì 20 maggio 2025
Maggio
19
Lunedì
Nicholas Hatsopoulos
nell'ambito della serie: NEUROMATEMATICA
ore
12:00
presso - Aula Da Stabilire -
The functional organization of primary motor cortex (M1) across the cortical sheet remains obscure. Aside from the crude and static somatotopic organization of M1, there is little evidence of spatially organized dynamic patterning across the motor cortical sheet. We have previously demonstrated that spatially organized propagating patterns of excitability along a rostro-caudal axis in non-human primates signal the initiation of movement but do not specify the details of the movement (Balasubramanian, Arce-McShane, Dekleva, Collinger, & Hatsopoulos, 2023). These propagating patterns of excitability were observed in the attenuation of low frequency beta oscillation (15-35 Hz) amplitude of the local field potential (LFP). We are now investigating patterns of high frequency components of the LFP (200-400 Hz referred to as high gamma) that propagate intermittently across M1 during reaching behaviors and have found that the propagation direction carries kinematic information (Liang, Balasubramanian, Papadourakis, & Hatsopoulos, 2023; unpublished data). Given that the high gamma signal serves as an accurate proxy for multi-unit activity (Ray & Maunsell, 2011), these results suggest that a spatially organized recruitment order of multi-unit activity provides behaviorally relevant information.
Maggio
19
Lunedì
Simona Paoli
nell'ambito della serie: LOGIC, CATEGORIES, AND APPLICATIONS SEMINAR
Seminario di algebra e geometria, logica, teoria delle categorie
ore
14:00
presso Seminario I
The simplicial category \Delta plays an important role in category theory. One of the reasons is that there is a fully faithful nerve functor from the category Cat to the category of simplicial sets (that is functors from the opposite of \Delta to Set). Its essential image consists of simplicial sets satisfying additional conditions that the Segal maps are isomorphisms. This allows to think of a small category as a type of simplicial set, and this idea has been carried on in higher dimensions in defining appropriate notions of higher categories. This talk is about a modification of \Delta, introduced by J. Kock, called the fat delta. After explaining the motivation for our interest in fat delta, both from higher category theory and from type theory, we present a study of fat delta in terms of monad with arities. This leads to a nerve theorem for relative semicategories, as well as a description of fat delta as a hypermoment categories in the sense of Berger. This is joint work with Tom de Jong, Nicolai Kraus and Stiephen Pradal, arXiv.2503.10963v1.
Maggio
21
Mercoledì
Marta Leocata
Seminario interdisciplinare
ore
10:00
presso - Aula Da Stabilire -
seminario on line •
Maggio
21
Mercoledì
Cristiano Bocci
Seminario di algebra e geometria
ore
14:30
presso Seminario I
In this talk I will introduce the main topics about the new field of research called Neuroalgebraic Geometry. In particular I will focus on the definitions, results (and conjectures) contained in the papers
- J. Kileel, M. Tranger, J. Bruna, On the Expressive Power of Deep Polynomial Neural Networks, (2019).
- K. Kubjas, J. Li, M. Wiesmann, Geometry of polynomial neural networks, (2024).
- G. L. Marchetti, V. Shahverdi, S. Mereta, M. Trager, K. Kohn, An Invitation to Neuroalgebraic Geometry, (2025).
and I will talk also about my recent results on it and a list of suggested problems.
Maggio
23
Venerdì
Frank Neumann
nell'ambito della serie: LOGIC, CATEGORIES, AND APPLICATIONS SEMINAR
ore
14:00
presso Seminario II
The Hochschild cohomology of a differential graded algebra or more generally of a differential graded category admits a natural map to the graded center of its derived category: the characteristic homomorphism. We interpret this map as an edge homomorphism in a spectral sequence, which allows to study the characteristic homomorphism systematically in many interesting examples from algebra, geometry, topology and physics. To illustrate this, we will discuss several concrete examples related to coherent sheaves on algebraic curves and cochains of classifying spaces of Lie groups. If time permits, I will also indicate a new extension of this framework to $A_\infty$-categories. Some of this is joint work with M. Szymik (Sheffield) other with A. Phimister (Leicester).
Maggio
26
Lunedì
Fosco Loregian
nell'ambito della serie: LOGIC, CATEGORIES, AND APPLICATIONS SEMINAR
ore
14:00
presso Seminario II
In this talk I will study generalized automata (in the sense of Adámek-Trnková) in Joyal’s category of combinatorial species; as an important preliminary step, I will provide examples of coalgebras for the "derivative" endofunctor ∂ and for the ‘Euler homogeneity operator’ L∂ arising from the adjunction L⊣∂⊣R.
The theory is connected with, and in fact provides nontrivial examples of, differential 2-rigs—a concept I recently introduced by treating combinatorial species in the same way that a generic (differential) semiring (R,d) relates to the (differential) semiring N[[X]] of power series with natural coefficients. Joyal himself has long regarded species as categorified formal power series. This perspective aligns with a fundamental category-theoretic insight: free objects in the category of rings naturally acquire a canonical differential structure. At the heart of this phenomenon lies the representability of the prestack of derivations by an object of Kähler differentials. These ideas categorify elegantly within the 2-category of differential 2-rigs, revealing that species possess a universal property as differential 2-rigs.
The desire to study categories of ‘state machines’ valued in an ambient monoidal category (K,⊗) gives a pretext to further develop the abstract theory of differential 2-rigs, proving lifting theorems of a differential 2-rig structure from (R,∂) to the category of ∂-algebras on objects of R, and to categories of Mealy automata valued in (R,⊗), as well as various constructions inspired by differential algebra such as jet spaces and modules of differential operators.
This talk covers the content of the paper Automata and Coalgebras in Categories of Species (Proceedings of CMCS24, Luxembourg), as well as parts of an ongoing project with Todd Trimble.
Maggio
dal giorno
29/05/2025
al giorno
30/05/2025
29/05/2025
al giorno
30/05/2025
Conference
da giovedì 29 maggio 2025
a venerdì 30 maggio 2025
Maggio
30
Venerdì
Matteo Viale
nell'ambito della serie: LOGIC, CATEGORIES, AND APPLICATIONS SEMINAR
Seminario interdisciplinare
ore
14:00
presso Seminario II
TBA
Giugno
03
Martedì
Marco Fava
nell'ambito della serie: SEMINARIO DI ALGEBRA E GEOMETRIA
Seminario di algebra e geometria
ore
11:00
presso Aula Vitali
Giugno
09
Lunedì
Matteo Marsili
nel ciclo di seminari: SEMINARS IN MATHEMATICAL PHYSICS AND BEYOND
Seminario di fisica matematica
ore
11:00
presso Aula Bombelli
Note: this is the first part of a two-part seminar.
AI is progressing at a remarkable speed, but we still don’t have a clear understanding of basic concepts in cognition (e.g. learning, understanding, abstraction, awareness, intelligence, etc).
I shall argue that research focused on understanding how learning machines such as LLMs or deep neural networks do what they do, sidesteps the key issue by defining these concepts from the outset. For example, statistical learning is based on a classification of problems (supervised/unsupervised, classification, regression etc.) and addresses the resulting optimisation problem (maximisation of the likelihood, minimisation of errors, etc). Learning entails first of all detecting what makes sense to be learned 1) from very few samples, and 2) without a priori knowing why that date makes sense. This requires a quantitative notion of relevance that can distinguish data that makes sense from meaningless noise. I will first introduce and discuss the notion of relevance.
Next I will claim that learning differs from understanding, where the latter implies integrating data that make sense into a pre-existing representation. The properties of this representation should be abstract, i.e. independent of the data, precisely because they need to represent data of a widely different domain. This is what enables higher cognitive functions that we do all the time, like drawing analogies and relating data learned independently from widely different domains. Such a representation should be flexible and continuously adaptable if more data or more resources are made available. I will show that such an abstract representation can be defined as the fixed point of a renormalisation group transformation, and it coincides with a model that can be defined from the principle of maximal relevance.
I will provide empirical evidence that the representations of simple neural networks approach this universal model as the network is trained on a broader and broader domain of data.
Overall, the aim of the seminar is to support the idea that an approach to central issues in cognition is also possible studying very simple models and does not necessarily require understanding large machine learning models.
Giugno
09
Lunedì
Philipp Schlicht
nell'ambito della serie: LOGIC, CATEGORIES, AND APPLICATIONS SEMINAR
ore
14:00
presso Seminario II
Giugno
09
Lunedì
Matteo Marsili
nel ciclo di seminari: SEMINARS IN MATHEMATICAL PHYSICS AND BEYOND
Seminario di fisica matematica
ore
14:30
presso Aula Arzelà
Note: this is the second part of a two-part seminar.
AI is progressing at a remarkable speed, but we still don’t have a clear understanding of basic concepts in cognition (e.g. learning, understanding, abstraction, awareness, intelligence, etc).
I shall argue that research focused on understanding how learning machines such as LLMs or deep neural networks do what they do, sidesteps the key issue by defining these concepts from the outset. For example, statistical learning is based on a classification of problems (supervised/unsupervised, classification, regression etc.) and addresses the resulting optimisation problem (maximisation of the likelihood, minimisation of errors, etc). Learning entails first of all detecting what makes sense to be learned 1) from very few samples, and 2) without a priori knowing why that date makes sense. This requires a quantitative notion of relevance that can distinguish data that makes sense from meaningless noise. I will first introduce and discuss the notion of relevance.
Next I will claim that learning differs from understanding, where the latter implies integrating data that make sense into a pre-existing representation. The properties of this representation should be abstract, i.e. independent of the data, precisely because they need to represent data of a widely different domain. This is what enables higher cognitive functions that we do all the time, like drawing analogies and relating data learned independently from widely different domains. Such a representation should be flexible and continuously adaptable if more data or more resources are made available. I will show that such an abstract representation can be defined as the fixed point of a renormalisation group transformation, and it coincides with a model that can be defined from the principle of maximal relevance.
I will provide empirical evidence that the representations of simple neural networks approach this universal model as the network is trained on a broader and broader domain of data.
Overall, the aim of the seminar is to support the idea that an approach to central issues in cognition is also possible studying very simple models and does not necessarily require understanding large machine learning models.
Giugno
13
Venerdì
Ilja Gogic
nell'ambito della serie: LOGIC, CATEGORIES, AND APPLICATIONS SEMINAR
Seminario di analisi matematica
ore
14:00
presso Seminario II
The most basic class of derivations on C*-algebras consists of the inner derivations—those expressible as commutators with elements from the multiplier algebra. A fundamental question in the theory of C*-algebras is to determine which algebras admit only inner derivations. Landmark results by Sakai, Kadison, and Sproston established this property for all von Neumann algebras, simple C*-algebras, and homogeneous C*-algebras. In the separable setting, the problem was completely resolved in 1979 by Akemann, Elliott, Pedersen, and Tomiyama, who showed that a separable C*-algebra has only inner derivations if and only if it is a direct sum of a C*-algebra with continuous trace and a C*-algebra with discrete primitive spectrum.
However, the non-separable case remains largely unsettled—even for 2-subhomogeneous algebras. In 1978, Pedersen posed a unifying question, inspired by the work of Sakai and Kadison: given a C*-algebra, does its local multiplier algebra—defined as the C*-direct limit of the multiplier algebras of its essential closed ideals—admit only inner derivations?
In this talk, we revisit the classical innerness problem for derivations on C*-algebras, highlighting both recent developments and emerging perspectives.
Giugno
dal giorno
16/06/2025
al giorno
18/06/2025
16/06/2025
al giorno
18/06/2025
Conference
Three Days in Sub-Riemmanian Geometry
da lunedì 16 giugno 2025
a mercoledì 18 giugno 2025
Giugno
dal giorno
16/06/2025
al giorno
18/06/2025
16/06/2025
al giorno
18/06/2025
Conference
Three Days in Sub-Riemannian Geometry
da lunedì 16 giugno 2025
a mercoledì 18 giugno 2025
Giugno
dal giorno
16/06/2025
al giorno
18/06/2025
16/06/2025
al giorno
18/06/2025
Conference
Three Days in Sub-Riemmanian Geometry
da lunedì 16 giugno 2025
a mercoledì 18 giugno 2025
Giugno
16
Lunedì
Paolo Perrone
nell'ambito della serie: LOGIC, CATEGORIES, AND APPLICATIONS SEMINAR
ore
14:00
presso Seminario II
Category theory was initially developed to address some structural questions in algebraic topology. Shortly after it was extended to algebraic geometry, logic, universal algebra, and more recently, theoretical computer science. Each of these subjects was heavily influenced by category theory, and in turn, the development of category theory was prominently shaped by the strucures and problems arising in these fields.
In the past few years there has been a growing interest in applying categorical techniques to fields such as probability, statistics and information theory, to study their structures and to find patterns in their techniques. Perhaps surprisingly, it turns out that these fields present a rich and principled structure when addressed categorically, with functors and universal properties arising everywhere.
However, most of the time, new category theory is needed to study these subjects, as they are quite far from the algebra and geometry for which category theory was initially developed.
Two of the current most prolific environments to study probability categorically are Markov categories and dagger categories. In this talk we will give an introduction to both, show their similarities, differences and connections, and use them to prove some core theorems of probability.
Giugno
18
Mercoledì
Giuseppina Guatteri
nell'ambito della serie: STOCHASTICS AND APPLICATIONS - 2025
Seminario di probabilità
ore
11:00
presso - Aula Da Stabilire -
seminario on line •
Giugno
23
Lunedì
Valentina Disarlo
nell'ambito della serie: LOGIC, CATEGORIES, AND APPLICATIONS SEMINAR
ore
14:00
presso Seminario II
Giugno
dal giorno
25/06/2025
al giorno
27/06/2025
25/06/2025
al giorno
27/06/2025
Conference
da mercoledì 25 giugno 2025
a venerdì 27 giugno 2025
Giugno
26
Giovedì
Miguel Urbano
nell'ambito della serie: SEMINARI DI ANALISI MATEMATICA BRUNO PINI
Seminario di analisi matematica
ore
16:00
presso Aula Arzelà
seminario on line •
collegamento al meeting
We substantially improve in two scenarios the current state-of-the-art modulus of continuity for weak solutions to the $N-$dimensional, two-phase Stefan problem featuring a $p-$degenerate diffusion: for $p=N\geq 3$, we sharpen it to
$\boldsymbol{\omega}(r) \approx \exp (-c| \ln r|^{\frac1N})$; for $p>\max\{2,N\}$, we derive an unexpected H\"older modulus. This is a joint work with Ugo Gianazza and Naian Liao.
Luglio
04
Venerdì
Gianluca Paolini
nell'ambito della serie: LOGIC, CATEGORIES, AND APPLICATIONS SEMINAR
Seminario di algebra e geometria, interdisciplinare, logica
ore
14:00
presso Seminario II
An uncountable $\aleph_1$-free group can not admit a Polish group topology but an uncountable $\aleph_1$-free abelian group can, as witnessed e.g. by the Baer-Specker group $\mathbb{Z}^\omega$, in fact, more strongly, $\mathbb{Z}^\omega$ is separable. In this paper we investigate $\aleph_1$-free abelian non-Archimedean Polish groups. We prove two main results. The first is that there are continuum many separable (and so torsionless, and so $\aleph_1$-free) abelian non-Archimedean Polish groups which are not topologically isomorphic to product groups and are pairwise not continuous homomorphic images of each other. The second is that the following four properties are complete co-analytic subsets of the space of closed abelian subgroups of $S_\infty$: separability, torsionlessness, $\aleph_1$-freenees and $\mathbb{Z}$-homogeneity.
Settembre
dal giorno
01/09/2025
al giorno
05/09/2025
01/09/2025
al giorno
05/09/2025
Conference
da lunedì 01 settembre 2025
a venerdì 05 settembre 2025
Summer School sponsored by the CIME Foundation
Local expenses for speakers are paid by CIME
Trave expenses for speakers to be reimbursed using the funds of the ERC project DAT
Ottobre
09
Giovedì
Moritz Egert
nell'ambito della serie: SEMINARI DI ANALISI MATEMATICA BRUNO PINI
Seminario di analisi matematica
ore
16:00
presso Aula Enriques
seminario on line •
collegamento al meeting
TBA