Notiziario Scientifico

Notiziario dei seminari di carattere matematico
a cura del Dipartimento di Matematica Guido Castelnuovo, Sapienza Università di Roma

Settimana dal 19-02-2024 al 25-02-2024

Lunedì 19 febbraio 2024
Ore 11:00, Aula "Roberta Dal Passo", Dipartimento di Matematica, Università degli Studi di Roma "Tor Vergata"
Corso di dottorato
Kirill Zainoulline (University of Ottawa)
Algebraic Cycles and Flag Varieties (Lecture 4)
Link to the class webpage: http://kirillmath.ca/acfv/

Lunedì 19 febbraio 2024
Ore 14:00, Aula Dal Passo, Dipartimento di Matematica, Università Tor Vergata
Mini-corso
Giovanni Conforti & Alain Dormus (École Polytechnique, Paris)
An introduction to Score-based Generative Models
Lecture 1 & Lecture 2. (Mon 19th, 14h00-17h00) Introduction to generative models & Probabilistic/statistical tools for generative models - Lecture 3 & Lecture 4. (Wed 21st, 09h30-12h30) A ”discrete” introduction to score-based diffusion models & A Itô-diffusion viewpoint on score-based diffusion models. - Lecture 5 & Lecture 6. (Thu 22nd, 09h30-12h30) Convergence bounds for score-based diffusion models via stochastic control & Optimal transport and entropic optimal transport for generative modeling.
Per informazioni, rivolgersi a: salvi@mat.uniroma2.it

Lunedì 19 febbraio 2024
Sede INdAM, Dipartimento di Matematica, Sapienza Università di Roma
INdAM Workshop
Innovations in the numerical treatment of stiff differential equations
Programma:

14:15-15:00 Manuel Castro (University of Malaga): Implicit exactly well-balanced finite volume schemes for balance laws with singular source terms
15:00-15:45 Andrea Thomann (INRIA Nancy-Grand Est): TVD-MOOD schemes based on implicit-explicit time integration
Coffee Break
16:15-17:00 Philipp Birken (Lund University): Iterative solvers vs linear and nonlinear invariants in CFD
17:00-17:45 Matteo Semplice (University of Insubria): Quinpi, or going implicit for nonlinear hyperbolic equations

Sito web https://sites.google.com/uniroma1.it/indam-workshop-insides/home

Lunedì 19 febbraio 2024
Ore 14:30, Sala di Consiglio, Dipartimento di Matematica, Sapienza Università di Roma
seminario di Analisi Matematica
Hardy Chan (Basel University)
Nonlocal approximation of minimal surfaces: optimal estimates from stability.
For stable nonlocal \(s\)-minimal surfaces in \(\mathbb{R}^3\) which approximate classical minimal surfaces (as \(s \to 1^-\)), we obtain robust \(C^{2,\alpha}\) estimates and optimal sheet separation estimates. The interaction between sheets is described by the (local) Dàvila-del Pino-Wei system. With a suitable extension of these estimates, we classify stable \(s\)-minimal hypersurfaces in \(\mathbb{R}^4\) as hyperplanes. Geometric applications are also discussed. This is a joint work with Serena Dipierro, Joaquim Serra and Enrico Valdinoci. This seminar is part of the activities of the Dipartimento di Eccellenza CUP B83C23001390001 and it is funded by the European Union – Next Generation EU.
Per informazioni, rivolgersi a: azahara.delatorrepedraza@uniroma1.it

Lunedì 19 febbraio 2024
Ore 16:00, Sala di Consiglio, Dipartimento di Matematica, Sapienza Università di Roma
Seminario di Probabilità
Giuseppe Cannizzaro (University of Warwick, UK)
Weak coupling scaling of critical SPDEs
The study of stochastic PDEs has known tremendous advances in recent years and, thanks to Hairer's theory of regularity structures and Gubinelli and Perkowski's paracontrolled approach, (local) existence and uniqueness of solutions of subcritical SPDEs is by now well-understood. The goal of this talk is to move beyond the aforementioned theories and present novel tools to derive the scaling limit (in the so-called weak coupling scaling) for some stationary SPDEs at the critical dimension. Our techniques are inspired by the resolvent method developed by Landim, Olla, Yau, Varadhan, and many others, in the context of particle systems in the supercritical dimension. Time allowing, we will explain how it is possible to use our techniques to study a much wider class of statistical mechanics models at criticality such as (self-)interacting diffusions in random environment.

Martedì 20 febbraio 2024
Sede INdAM, Dipartimento di Matematica, Sapienza Università di Roma
INdAM Workshop
Innovations in the numerical treatment of stiff differential equations
Programma:

9:15- 10:00 Giovanni Russo (University of Catania): Weakly nonlinear shallow water waves over periodic bathymetry
10:00-10:45 Giulia Bertaglia (University of Ferrara): Multiscale computational modeling of blood flow with asymptotic-preserving schemes
Coffee Break
11:15-12:00 Raul Borsche (TU Keiserslautern): Implicit Active Flux methods for district heating networks
12:00-12:45 Sigrun Ortleb (University of Kassel): Accuracy and Stability of IMEX Upwind SBP Schemes for Advection-Diffusion and Linear Kinetic Transport Problems
Lunch
14:15- 15:00 Thomas Rey (University of Nice): Discrete hypocoercivity for a nonlinear kinetic reaction model
15:00-15:45 Irene Gomez-Bueno (University of Malaga): Asymptotic-preserving and well-balanced methods for stiff PDEs
Coffee Break
16:15-17:00 Giacomo Albi (University of Verona): High-order IMEX and semi-implicit multistep methods for evolutive partial differential equations

Sito web https://sites.google.com/uniroma1.it/indam-workshop-insides/home

Martedì 20 febbraio 2024
Ore 11:00, Aula "Roberta Dal Passo", Dipartimento di Matematica, Università degli Studi di Roma "Tor Vergata"
Corso di dottorato
Kirill Zainoulline (University of Ottawa)
Algebraic Cycles and Flag Varieties (Lecture 5)
Link to the class webpage: http://kirillmath.ca/acfv/

Martedì 20 febbraio 2024
Ore 13:00, Diapartimento di Matematica e Fisica, Via della Vasca Navale, 84 - Aula C, Università di Roma Tre
Seminario di crittografia
Elena Ciampedel (Università degli Studi de l'Aquila)
An overview of Secure Twoparty Computation
Secure Two-party Computation (2PC) was introduced in 1982 by Yao to address the so-called millionaires problem: "two millionaires wish to know who is richer; however, they do not want to find out inadvertently any additional information about each other's wealth". More generally, 2PC is a special case of multiparty computation, in which two distrusting parties wish to jointly compute a function of their private inputs without revealing anything other than what can be inferred from their own input and prescribed output. In this talk, we will retrace some of the fundamental stages for 2PC, starting from the ideas developed, in the late 1980s, by Yao on the one hand, and Goldreich, Micali and Wigderson on the other hand.

Martedì 20 febbraio 2024
Ore 14:15, Laboratorio di Calcolo 1, Dipartimento di Matematica, Sapienza Università di Roma
Corso di Dottorato
Sandro Teta (Sapienza università di Roma)
Elementi di storia della meccanica quantistica (V)

Martedì 20 febbraio 2024
Ore 14:30, aula D'Antoni, Dipartimento di Matematica, Università di Roma Tor Vergata
seminario di Geometria
Maksym Fedorchuk (Boston University)
CM-minimizers and standard models of Fano fibrations over curves
A recent achievement in K-stability of Fano varieties is an algebro-geometric construction of a projective moduli space of K-polystable Fanos. The ample line bundle on this moduli space is the CM line bundle of Tian. One of the consequences of the general theory is that given a family of K-stable Fanos over a punctured curve, the polystable filling is the one that minimizes the degree of the CM line bundle after every finite base change. A natural question is to ask what are the CM-minimizers without base change. In answering this question, we arrive at a theory of Kollár stability for fibrations over one-dimensional bases, and standard models of Fano fibrations. After explaining the general theory, I will sketch work in progress on standard models of quartic threefold hypersurfaces. This talk is based on joint work with Hamid Abban and Igor Krylov.
Per informazioni, rivolgersi a: guidomaria.lido@gmail.com

Martedì 20 febbraio 2024
Ore 18:00, Aula Picone, Dipartimento di Matematica "Guido Castelnuovo" Sapienza Università di Roma
Seminario di Algebra e Combinatoria
Loic Foissy (Université du Littoral Cote d'Opale - Calais)
Algebraic structures on noncrossing partitions
The theory of free probabilities uses the combinatorics of noncrossing partitions in order, for example to establish relations between free cumulants and moments of a random variable. We shall describe the underlying algebraic structures (operads and Hopf algebras). This a joint work with Kurusch Ebrahimi-Fard, Joachim Kock and Frédéric Patras.
Per informazioni, rivolgersi a: claudia.malvenuto@uniroma1.it

Mercoledì 21 febbraio 2024
Aula 17 della Facoltà di Ingegneria in San Pietro in Vincoli, Sapienza Università di Roma
Workshop
RAM3 - Recent Advances in Mechanics and Mathematics of Materials
Pagina web https://sites.google.com/a/uniroma1.it/ram3/home

Mercoledì 21 febbraio 2024
Sede INdAM, Dipartimento di Matematica, Sapienza Università di Roma
INdAM Workshop
Innovations in the numerical treatment of stiff differential equations
Programma:

9:15- 10:00 Adrian Sandu (Virginia Tech): Hybrid Time Integration Algorithms for Multiscale Multiphysics Systems
10:00-10:45 Davide Torlo (University of Trieste): IMEX ADER and DeC: arbitrary high order schemes, stability and application to advection--diffusion--dispersion
Coffee Break
11:15-12:00 Sandra May (Uppsala University): Explicit implicit finite volume schemes for meshes with tiny cells
12:00-12:45 Philipp Oeffner (University of Mainz): Discussions about stability of modified Patankar schemes and about their application as time-integrators in hyperbolic balance equations
Lunch

Sito web https://sites.google.com/uniroma1.it/indam-workshop-insides/home

Mercoledì 21 febbraio 2024
Ore 14:00, Sala di Consiglio, Dipartimento di Matematica, Sapienza Università di Roma
Seminario di Algebra e Geometria
Carlo Collari (Università di Pisa)
Groebner methods and magnitude homology
In this talk we show how to apply the framework developed by Sam and Snowden to study structural properties (eg. bound on rank and order of torsion) of graph homologies, in the spirit of Ramos, Miyata and Proudfoot. In particular, we focus on magnitude homology for graphs, which was introduced by Hepworth and Willerton. The talk is organised as follows; we start with a short introduction to modules over categories and to the theory of Groebner categories. Then, we introduce magnitude homology and see some examples. Finally, we will see how to use the theory of Groebner categories to obtain information on magnitude (co)homology.

Mercoledì 21 febbraio 2024
Ore 14:15, online (zoom), registrazione disponibile alla pagina https://indico.gssi.it/event/410/
ciclo Mathematical Challenges in Quantum Mechanics
Fumio Hiroshima (Kyushu University)
Renormalized spectral zeta function of Rabi model
Disponibile al link https://indico.gssi.it/event/410/attachments/726/1782/hiro.pdf
Per informazioni, rivolgersi a: monaco@mat.uniroma1.it

Giovedì 22 febbraio 2024
Aula 17 della Facoltà di Ingegneria in San Pietro in Vincoli, Sapienza Università di Roma
Workshop
RAM3 - Recent Advances in Mechanics and Mathematics of Materials
Pagina web https://sites.google.com/a/uniroma1.it/ram3/home

Giovedì 22 febbraio 2024
Sede INdAM, Dipartimento di Matematica, Sapienza Università di Roma
INdAM Workshop
Innovations in the numerical treatment of stiff differential equations
Programma:

9:15- 10:00 Todd Arbogast (University of Texas): Self Adaptive Theta (SATh) Schemes for Solving Hyperbolic Conservation Laws
10:00-10:45 Maya Briani (IAC-CNR): On implicit time schemes and discontinuous Galerkin space reconstruction for conservation laws
Coffee Break
11:15-12:00 Inmaculada Higueras (Public University of Navarre): IMplicti-EXplicit time stepping methods for stiff problems in astrophysics
12:00-12:45 Giuseppe Orlando (Ecole Polytechnique): An asymptotic-preserving scheme for Euler equations with non-ideal gases
Lunch
14:15- 15:00 Giuseppe Izzo (University of Naples): Self Starting Implicit-Explicit General Linear Methods
15:00-15:45 Sebastiano Boscarino (University of Catania): High-Order Semi-implicit Schemes for Evolutionary Partial Differential Equations with Higher Order Derivatives
Coffee Break
16:15-17:00 Jochen Schuetz (University of Hasselt): Implicit/explicit multiderivative methods

Sito web https://sites.google.com/uniroma1.it/indam-workshop-insides/home

Giovedì 22 febbraio 2024
Ore 14:15, Aula M1, Dipartimento di Matematica e Fisica, Università Roma Tre
Seminario di Geometria
Maksym Fedorchuk (Boston College)
A report on some recent progress around F-conjecture
Mumford famoulsy asked to describe the ample cone of the moduli space of Deligne-Mumford stable curves \(\bar M_{g,n}\), or, dually, its Kleiman-Mori cone of curves. Conjecturally the answer is given by a well-known F-conjecture that states that the cone of curves is spanned by the one-dimensional boundary strata called the F-curves. A breakthrough Bridge Theorem of Gibney-Keel-Morrison reduces the positive genus case to the case of g=0. In genus 0, the F-conjecture for \(\bar M_{0,n}\) is implied by the strong F-conjecture which is true up to \(n \leq 7\) and fails for \( n \geq 12\) by Pixton's counterexample. I will report on joint work with Anton Mellit in which we prove the strong F-conjecture for n=8, the F-conjecture for \(\bar M_{g}\) for \(g \leq 44\) and a bit more.
Per informazioni, rivolgersi a: amos.turchet@uniroma3.it

Giovedì 22 febbraio 2024
Ore 14:30, Aula 1B1, RM002, Via Scarpa 16, Dipartimento SBAI
Seminario "PDE a tutto SBAI"
Antonio Jesus Martinez Aparicio (Universidad de Almeria (Spagna))
Semilinear elliptic eigenvalue problems with infinitely many positive solutions
We study the behavior of the set of solutions of the semilinear elliptic problem -Δu = λf(u) in a bounded N-dimensional open set with Dirichlet boundary conditions. Here, f is a nonnegative continuous real function with multiple zeros. First, we analyze the set of the solutions whose maximum is between two consecutive positive zeros of f, arriving to the existence of an unbounded continuum of solutions with C-shape. Then, we study the asymptotic behavior of the countable many unbounded continua in the case in which f has a sequence of positive zeros, proving for some model cases that every λ>0 is a bifurcation point (either from infinity or from zero) that is not a branching point.
Per informazioni, rivolgersi a: francesco.petitta@uniroma1.it

Venerdì 23 febbraio 2024
Sede INdAM, Dipartimento di Matematica, Sapienza Università di Roma
INdAM Workshop
Innovations in the numerical treatment of stiff differential equations
Programma:

9:15- 10:00 Dmitri Kuzmin (TU Dortmund): On the design and analysis of property-preserving finite element schemes for hyperbolic conservation laws
10:00-10:45 Abhijit Biswas (KAUST): Stiff Order Conditions in Runge-Kutta Methods for Linear and Semilinear Problems
Coffee Break
11:15-12:00 Simone Cacace (Sapienza University): SLBW: towards a Semi-Lagrangian Barycentric Walk library for PDEs on unstructured grids
12:00-12:45 Peter Frolkovic (University of Bratislava): Unconditionally stable compact implicit and semi-implicit numerical methods for some hyperbolic problems
Lunch

Sito web https://sites.google.com/uniroma1.it/indam-workshop-insides/home

Venerdì 23 febbraio 2024
Ore 12:00, Sala di Consiglio, Dipartimento di Matematica, Sapienza Università di Roma
seminario MoMA
Giovanna Jona Lasinio (Sapienza Università di Roma)
Learning about marine life by merging different data sources
Understanding population status is often challenged by scant abundance and distribution data for many threatened species both in marine and terrestrial environments. Occurrence records are often scarce and opportunistic, and fieldwork to retrieve additional data is expensive and prone to failure, particularly if the species is highly mobile. Integrating various data sources becomes crucial to developing species distribution models for informed sampling and conservation purposes. Dolphins, sea turtles and other cetaceans are currently monitored in the Italian Mediterranean. ISPRA, Sapienza and other scientific institutions implemented several rigorous survey designs to collect presence data on these species. However, due to the high cost, these designs explore only a specific portion of the Italian Mediterranean, limiting the generalization of the results. Other marine species, such as the white shark, are rare but persistent inhabitants of the Mediterranean Sea. Information on the species' presence is almost never connected to rigorous surveys. Here, we will explore some examples where occasional sightings ("citizen science") of a species are included in the species distribution model. Two issues are presented and addressed: 1- the data records only the presence (no information on the absence is available) 2- the occasional sightings are not connected to a known observation mechanism, and this, too, is a serious issue!
Per informazioni, rivolgersi a: basile@mat.uniroma1.it, adriana.garroni@uniroma1.it

Venerdì 23 febbraio 2024
Ore 16:00, Aula Picone, Dipartimento di Matematica, Sapienza Università di Roma
Seminari per i docenti A.A. 2023-2024
Maria Anna Raspanti, Giuliana Massotti, Lorenzo Mazza, Maristella Petralla
Irrazionalità: provare per credere!

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